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mkpontiac
Buffalo

52 Posts

Posted - 24 May 2007 :  12:57:34 AM  Show Profile  Reply with Quote
I have enjoyed reading the post on this site and have learned a lot. Thanks for all your knowledge.

I am considering the Crower cam 60916 for my 69 Grand Prix
400Ci
Stock #62 Heads
4barrel Quadrajet
Currently cast pistons with 8 valve relief’s – milled for approximately 9.0:1 compression
3.23 rear end and stock converter
TH400
I am considering using Rhoads lifters with the cam to maximize low end torque and improve idle and fuel economy.

Is this a good combination for a car that will only be driven on the street?
Is the compression ratio correct considering I would be using the Rhoads lifters? I realize the recommended compression ratio for that cam is 10.5:1 but I thought the Rhoads lifter would require that it be lower.

What would be the approximate horse power of this combination?

Vacuum at idle?

Your input is appreciated

Mark


73TA455
Buffalo

USA
77 Posts

Posted - 24 May 2007 :  10:34:43 PM  Show Profile  Reply with Quote
I would agree no need for the Rhoads lifters with the 60916. Probably work fine with normal lifters. I’m using Rhoads lifters with 60243 and 1.65 rockers (in a 455 however) and I have plenty of low-end and it idles at 800 RPM with 12 inches of vacuum. The 60243 is a somewhat larger cam than the 60916 especially with my 1.65 rockers. Good luck, it should run very good either way.


RL Edwards
1973 Trans Am
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Will
Cochise

Zimbabwe
285 Posts

Posted - 25 May 2007 :  02:19:22 AM  Show Profile  Reply with Quote
What have you guys got against the Rhoads lifters?

Is it the ticking at idle? Why not ask mkpontiac if he's aware that they tick at idle and whether that's a problem for him, as it seems to be for you?

If he doesn't mind the ticking (I didn't in either engine I ran them in) then they will substantially boost low end torque with that cam, and that will be a good thing with 3.23 gears and a stock converter.

I read a comment somewhere on one of the boards not long ago about how someone changed out his Rhoads lifters because the noise drove him crazy on a long drive...???? That doesn't make any sense to me, the only time you should hear the Rhoads is at idle when they're bleeding down. At higher engine speeds they don't bleed down and the ticking goes away.

I guess I'm just weird, but if I know what the noise is and understand it's purpose, then it doesn't bother me. A little ticking at idle was just fine when combined with the sound of the mildly burbling exhaust...

I can't comment on how much vacuum that combo will have as I don't know anyone running that particular combo nor have I run it myself, but I will go out on a limb and say that vacuum will be "more than adequate," comparable to a cam with 10 degrees less duration, so probably in the 15" or greater range.

Not qualified to answer questions about engines over 425 HP.
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dennismac
Cochise

270 Posts

Posted - 25 May 2007 :  02:41:29 AM  Show Profile  Reply with Quote
Rhodes added about 10" of vaccuum with my 041 cam but still has the power at mid range rpms. They seeed to have smoothed out the powerband. I would rather have a cam with the higher lift/duration plus the benefits of of a low end cam as well. The rhoades gives you that choice. Until a cam is developed that has a performance range from idle to 6000 rpms, rhoads lifters give you that choice. I have heard that either comp or crane is now making something that sounds similar.
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Cliff
Cochise

USA
289 Posts

Posted - 25 May 2007 :  05:18:22 AM  Show Profile  Reply with Quote
The 60916 is a bit too much cam for the 9 to 1 400 engine. You would be much happier with a slightly smaller cam, closer to the specs of a stock 068 grind. You'd be much better off with a 214/224/112 grind, or something very close to those specs.

We like to see at least 10 to 1 static CR for the 60916, and at least a 2500rpm stall speed converter, FWIW....Cliff

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Mr. P-Body
Running Bear

USA
2258 Posts

Posted - 25 May 2007 :  08:37:37 AM  Show Profile  Visit Mr. P-Body's Homepage  Reply with Quote

To add to what Cliff says, we've found the the Comp XE grinds to be VERY "friendly" to lower compressoin ratios (under 10:1). We (Cliff and I) recently brainstormed a compression/cam situation regarding these issues. We (CVMS) had a 455 (plus .030) with too much compression (9.7:1) for 93 octane. The two basic choices were to use the XE274H cam and reduce the ratio, OR... Use the 041 cam and allow the cylinder pressure to "bleed off" at lower RPM. We opened the chambers a bit, and went with the Comp. The low-end and vacuum signal would be more desirable in the street application.

Charley Reichardt, of Cam Craft in Maryland, has sent flyers to all his regular customers (we use Cam Craft for antiques and "odd" grinds) concerning "fast-bleed" lifters. He states quite clearly, using a fast-bleed lifter, such as Rhoads, is more a pactch for a poor cam choice, than it is a good performance modification. We agree. In olden times, when cam selection for the Pontiac was spotty and limited, they (fast-bleeds) were a viable choice. Today, there's absolutely no reason to use them, as the entire spectrum of cam grinds are available for the ol' Injun. If you would have been at PITP, and seen/heard all the solid roller street engines running around, you would KNOW, these cams are great!

This is not to say everone that doesn't agree is "wrong", just to let everyone know, there are better alternatives using modern technology. A modern performance engine doesn't NEED to lope and jump around to make BIG power. And Pontiacs are no exception!

FWIW

Jim
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Cliff
Cochise

USA
289 Posts

Posted - 26 May 2007 :  08:18:02 AM  Show Profile  Reply with Quote
Just to add a few thoughts to what Jim posted. The cam should always be selected carefully for each application, based on the true static compression ratio, drivetrain specifications, use of the vehicle, etc.

Several years ago, we had our own 455 out for "freshening" up, so I decided to install a flat solid cam to replace the "old" Crower RAIV grind. I talked with Jeff Kauffman at KRE, we went into Comp's catalog and looked at lobe profiles, and ended up picking a Comp XTQ solid grind, 240/248/112. On paper, the cam looked fantastic, sporting improved .050", .200" numbers over the 231/240/113 Crower grind. It also sported a LOT more lift, up near .580" with the rockers we use, compared to .530" lift with the old cam.

The cam should have made more power across the rpm range. On the dyno, it was down 10Hp and 22 ft lbs torque, we tuned on it all day and couldn't find any more power. We tried moving the cam around, and using tighter lash, etc, the power simply was NOT there.

I decided to move up to a hydraulic roller grind, to duplicate as closely as possible, the Crower RAIV grind lobe placement, specs, etc. The new roller sports 230/242/112 specs.

While waiting for the new cam, I did some further investigating, into the XTQ grind. Although it sported much more "agressive" lobes, with "modern" profiles, it gave up valve time off the seat, or actual duration at .006" tappet movement. Our old Crower grind sported around 308/320 actual duration, the new grind was down around 288/298 (nearly as I can remember). My engine, sees the increased valve time off the seat as an opportunity to move air, therefore made more power and pulled further into the RPM range. The XTQ grind was DONE on the dyno at 5200rpm's, our RAIV grind made peak power to 5600.

Moral of the story. There is absolutely NOTHING at all wrong with the new cam, or the technology, we simply did NOT pick the cam with enough actual duration so that it would make as much or more power as the old grind. Without knowing it, I simply installed a "smaller" cam, and it took a few HP out of the engine. We did notice that the newer cam, idled with about four MORE inches of vacuum than the cam it replaced. This should have clued me in before making pulls, that we had taken some upper mid-range and top end power out of the engine.

As for the Rhoad's lifters. We ran our 60919 cam for over 5 years, starting out with standard lifters, and after one season installing Rhoad's lifters. The Rhoad's lifters improved vacuum at idle from 6-7" to about 10-11". We saw NO improvment whatsoever at the track, as our converter flashes to 3500rpm's, well beyond where the Rhoad's are fully "pumped-up" and functioning as normal lifters. We did enjoy improved idle quality, and crisper throttle response right off idle, with some additional power below about 2500rpm's.

We removed the cam and lifters, after over 1100 documented runs, and at least 10,000 street miles. The cam lobes were perfect, as were the lifters, nicely polished to a mirror finish. We gave the cam and lifters to a fellow enthusiast, building a RAIV engine, where they are still in use without any problems.

Aside from some "ticking" at idle speed, we never had any troubles whatsoever with the Rhoad's lifters. I actually liked the sound, reminded me of having a solid cam installed. I would also add that our "old" RAIV cam, and the Rhoad's lifters, managed 11.64 at just under 117mph, in full street trim, at 3760lbs race weight. This was in near perfect track conditions. Not to bad for "old" technology. Our new roller cam runs a bit quicker, managing 11.50's in hot/humid conditions, at just under 118mph......Cliff

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Will
Cochise

Zimbabwe
285 Posts

Posted - 26 May 2007 :  1:26:28 PM  Show Profile  Reply with Quote
Cliff, Jim - I really respect your opinions and you certainly have a lot more experience than I do building different combinations but I honestly don't understand the comments about Rhoads lifters being a "crutch" for an improperly selected cam.

Sure, there are all kinds of cam grinds available these days but certain truths about cam selection remain - most notably being that if you want higher RPM power you will trade off vacuum at idle and low speed torque because you must run more duration to get the higher RPM power. There's just no getting around that. Yes, a roller cam will offer improved low end compared to a flat tappet cam with similar specs but rollers are expensive and still may not offer the low speed characteristics that the Rhoads lifters do.

In this case we're looking at a 9:1 engine with 3.23 gears and a stock converter. If regular lifters were to be used I'd definitely be advocating the use of a cam with 212 @ .050" or less duration, preferably on a tighter lobe separation. But, such a cam won't make as much power above 4000 RPM as the Crower cam will. Overall, performance of the smaller cam would probably be better because the car would have more power to get off the line and could be short-shifted to stay in the relatively short power band.

Now take the Crower cam and put the Rhoads lifters on it. What you've effectively done is added variable valve timing to the equation. At low RPMs the cam will act like one that is 10 degrees smaller and slightly more advanced. In essence, it will have the same or very similar power characteristics to the smaller cam discussed above BUT once the RPMs get up to 3000 or so the lifters are all pumped up and the cam continues to make power higher into the RPM range because it's actually bigger than that little cam. Overall, this seems like an ideal situation. While it may not be as high tech and sophisticated as the VVT systems the OEMs are using now, it achieves the same basic thing.

So why the hating on the Rhoads? Will the 60916 not actually make more power at higher RPMS than a smaller cam would? Will the Rhoads lifters not tame the 60916 at lower RPMs making it behave like a smaller cam? How is that a "crutch" or "band aid" for an improperly selected cam? Sounds more like a tool or technique for building an engine with the broadest possible torque band to me, given the other limitations of the engine and combination.

Not qualified to answer questions about engines over 425 HP.
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dennismac
Cochise

270 Posts

Posted - 27 May 2007 :  12:37:27 AM  Show Profile  Reply with Quote
I think the rhoades do what they advertise- improve low end driveability for cams that may not have it. My recent experience with the same engine changing only the lifters with the o41 makes it possible to drive the car with the automatic like a normal street car. Since I don't race, i can't attest to that aspect, but i don't think the lifters were designed to improve 1/4 mile performance. I think if a car was built with the lifters, cam, transmission, and gearing all considered, a car with highway gears could pick up performance at the track while not giving up fuel economy. But if you are stalling at over 3000 rpms, the lifters are going to do nothing for you.
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Cliff
Cochise

USA
289 Posts

Posted - 27 May 2007 :  07:26:14 AM  Show Profile  Reply with Quote
Will, I have never said, or tried to indicate there is anything wrong with the Rhoad's lifters. We have used them here for years without any troubles in any area. They will help improve idle quality, and power right off idle. With a cam such as the 041 grind, known for low vacuum at idle speed, they will improve idle quality dramatically. They also improve throttle response right off idle, and low rpm power.

What they do NOT do, is change the power characteristics of the camshaft from about 2500 rpm's and up. We ran a dyno run with them once, and cranked the dyno down to just under 3000rpm's (low as it would go) to record power numbers, same with Rhoad's and standard lifters. If your combination uses a converter/drivetrain parts that load the engine heavily below 3000rpm's, then Rhoad's lifter will show a performance improvement at the track, with moderate to large duration camshafts.

When we build engines here, we pick the cam as closely as possible, for the combination. I don't try to overcam the engine, then add bleed down lifters to improve overall vehicle performance. For the engine in this particular thread, looking closely at the vehicle and drivetrain specs, I personally don't believe the 60916 cam is the best overall choice, even if Rhoad's lifters were added to it. I would use a cam with around 214/224/112 specs, or close to the 068 grind.

I would not use, or recomend, in any 400 application street application, in a vehicle with near stock drivetrain parts, the use of any of the smaller cams on tight LSA's. Different story when you start selecting larger cam, near and past about 240 degree's @ .050", for more "spirited" applications.....Cliff

If you can read this, thank a teacher, if you can read this in English, thank a Veteran!
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 28 May 2007 :  12:08:20 PM  Show Profile  Reply with Quote
Pitts, I am having a senior moment here. Is your hydro alum. or cast iron case?

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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mkpontiac
Buffalo

52 Posts

Posted - 28 May 2007 :  4:45:01 PM  Show Profile  Reply with Quote
Thank you all for your insight. After reading your advice I have been looking through several cam catalogs online. Cliff, I interpret being over cammed as meaning my compression ratio is too low for the 60916 cam so I am looking for something closer to my compression ratio. I like the Crower cam catalog because it gives the best description of how the cam will react in an engine based on cubic inches and a performance level unlike other catalogs that species 265-455 on the cubic inches. All the Crower cams I am looking at have the recommended intake centerline at 108.

Level 2 cams should have up to 9.5:1 compression for maximum performance while level 3 cams should have between 9.5:1 and 10.5:1. Level 4 should have a minimum of 10.25:1. So I should be looking at level 2 or slightly more. The 60916 although not listed under the 400 would probably be listed under a level 4 since it is a level 3 for the 428-455 so as you stated it is too much cam. However the 60242 is listed for the 400 as a level 3 – 280/286, 221/229 @ 0.050 and .456/.468 lift which has very similar characteristics to the 60916 on paper.

#60918 which is a “level 3” for the 370-421 ci – 288/298 advertised 214/224 @ 0.050 .444/.667 lift.
#60241 which is “level 3” for the 301-350 ci and a “level 2” for the 428-455 ci – 276/281 advertised, 215/221 @ 0.050 and .457/.464 lift. This one is not listed for the 400 so I guess it would be a performance level 2.5 which makes sense compared to the 60918 since the off seat time(Advertised duration) is less which should work slightly better for a lower compression engine.

I realize these are general catalog recommendations and real world experience may be different. Out of these cams would I be correct in selecting the #60241 for my combination because it would be closer to the recommended compression ratio?

The summit 2801 has 272/282 advertised, 214/224 @0.050 and .442/.465 lift with 107 intake centerline. From the specification I would guess this will perform similar to the #60241 but with a little more exhaust duration.

The Crane H-272-2 has 272/284 advertised, 216/228 @ 0.050 and .454/.480 lift with 107 intake centerline. This one is also very similar to the Summit 2801 but with slightly more lift and a bit more duration @0.050 but similar off the seat time. The slightly earlier intake center line should help a little with the lower compression. Crane specifies a compression ratio of 8.75:1 to 10.5:1 but does not specify cubic inches and I suspect that more cubic inches would benefit from more compression with the same cam.

Which of the above cams would you recommend for my application? Are any significantly better then the others? Although it may not be necessary from a vacuum stand point would there be any mpg benefit to adding the Rhoads lifters? Would it increase cylinder pressure too much at the lower RPM?

Thus far all cams listed have the 112 lobe separation angle. Mr. P-Body commented on the newer technology specifically the Comp Cams XE series. The XE262H seems to be a good selection with a description of “Excellent response, good mileage, stock converter and mild gear.” Specifications are 262/270 advertised, 218/224 @ 0.050,.462/.470 lift, 110 lobe centers with 106 intake center line. The online dyno sheets show a sbc 350 with Dart S/R heads and 9.25:1 compression pulling 348hp at 5300rpm and 17.5” vacuum at 800 rpm with no load. An extra 50ci would probably add an additional 30+ hp roughly 400 rpm sooner and 1-2” more vacuum. I suspect my heads may not flow as well as the Dart S/R so my overall numbers may be lower. I realize sbc are not the same as pontiacs but from what I can tell, this should be a good cam for the application. You insight is again appreciated.

MKPontiac
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mkpontiac
Buffalo

52 Posts

Posted - 31 May 2007 :  11:27:10 PM  Show Profile  Reply with Quote
Sorry for my last long winded post. What I wanted to know was if there is a significant difference in performance between the following cams for my 400, 9.0:1 with 3.23 gears?

#60241– 276/281 advertised, 215/221 @ 0.050 and .457/.464 lift. 108 intake centerline – 112LSA

Summit 2801 - 272/282 advertised, 214/224 @0.050 and .442/.465 lift with 107 intake centerline – 112LSA.

The Crane H-272-2 has 272/284 advertised, 216/228 @ 0.050 and .454/.480 lift with 107 intake centerline -112LSA.

XE262H - 262/270 advertised, 218/224 @ 0.050,.462/.470 lift, 110LSA with 106 intake centerline.
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Cliff
Cochise

USA
289 Posts

Posted - 01 Jun 2007 :  06:42:34 AM  Show Profile  Reply with Quote
Not really. The only one of those cams we've ever used is the 2801. I'd opt for the Crower cam, we have had excellent success with their cams. I ran a 210/221/112 cam in a previous engine that powered the Ventura. It had a 400, with 6X-8 heads, 7.7 to 1 compression ratio, stock converter and 2.73 gears. It would run 14.0-14.20's most of the time, with a best ever 13.87 at 101mph. The engine made a LOT more power than I ever thought it would, and was used for commuting back and forth to work in that configuration for years. Typically delivered 16-17 mpg's, probably would have done better if I could have kept my foot out of it!....Cliff

If you can read this, thank a teacher, if you can read this in English, thank a Veteran!
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Mr. P-Body
Running Bear

USA
2258 Posts

Posted - 01 Jun 2007 :  08:31:28 AM  Show Profile  Visit Mr. P-Body's Homepage  Reply with Quote

We've used XE262H in a LOT of engines. No complaints of ANY kind, including the "noise" the larger XE cams are known for. This cam will provide very good low-speed performance, as well as good power through 5,000. We use this cam as an 068/744 "replacement" in resto engines where the compression has been reduced for 93 octane fuel.

I've tried in the past, to "educate" people about comparing camshafts. While SOME of the parameters are common to all, lobe shape is a significant factor not considered when "comparing". An XE grind on a 110 LSA, is not going to "act" like a Crower on the same LSA. ALL the XE grinds are on a 110 LSA. Comp engineers are as good as any out there. The majority of complaints we hear about XE cams come from those deviating from Comp's design.

One solid example is Mike Palmer's Firebird convertible, 406 CID, 8.8:1. It put 256 RWHP down (on Greg's dyno), going 13.70s (on regular 2.25/70-15 Goodrich T/As) and getting 18 MPG. Pretty hard to argue with...

Jim
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mkpontiac
Buffalo

52 Posts

Posted - 03 Jun 2007 :  7:18:31 PM  Show Profile  Reply with Quote
Thank you. Real world examples and knowledge are helpful especially in choosing the correct cam for an application.

Mark
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keithnh
Tribal Scout

USA
14 Posts

Posted - 23 Jan 2014 :  04:12:51 AM  Show Profile  Reply with Quote
Designing backwards ... I see this is an old thread but have a question that might help myself and others. Was wondering as Rhoads lifters are still offered and seem to have a following, what would the specs-particulars on a camshaft selection made with the intention of using them be? instead of using them as a secondary crutch to get low end response from a big camshaft? Is the effect they have predictable enough to be included in HP TQ planning curves/numbers so that the best possible cam could be ground or chosen to make use of it? I think we are all interested in having as wide a torque band as possible and would not be unhappy with additional fuel economy. Im surprised not to see cam kits from Rhoads unless they just choose not to get in that business.

Heres a scenario, you are trapped on a desert island,there is nothing but Rhoads lifters for all applications and you really want to be competitive in the street/strip class with your 400P powered 64 GTO. In your 66 Star Chief 455P combo, and the 326 or 350P in your Astre. Classes are divided by rear-gear ratios starting @ 2.56 no higher than 3.73 Top three aftermarket cams. What you would spec as a custom?

Keith
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bigD
Indian Spirit

USA
643 Posts

Posted - 23 Jan 2014 :  12:16:01 PM  Show Profile  Reply with Quote
I really don't care what the experts say about Rhoads lifters. I used nothing but Rhoads in all our bracket racers from the Late '70's on. If I remember correctly, my 1st set was in 1977 in a mild 400 with an 068 cam, in a '68 Bird. TJ won the biggest race in south Ark that year, running a TH400 with a stock 13" converter.

After that we switched over to 455's with RA4 cams(Melling SPC-8), and Rhoads lifters. Again, we ran only stock 13" converters. The combo provided enuff bottom end to leave the line from an 800rpm idle and put a little air under the left front tire.

We won 15 races that year and won at least a few bucks at 69% of the races. TJ won the IHRA points race at Tyler, Texas. The next year I won the biggest race of the year at Tyler. No, I'm not braggin. I'm telling ya'll that Rhoads lifters WORK, exactly as advertised.

They extend the power range of any cam, by giving it a smoother idle and more low end torque, without sacrificing top end power. That's a combo that simply cannot be duplicated with any cam grind, no matter how new or modern it might be, using regular lifters. It's too late to try and convince me otherwise. I've still got copies of a lot of winners checks to remind me that they do work !


Edited by - bigD on 23 Jan 2014 12:30:19 PM
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Cobrabill
Talking Dog

Aruba
3128 Posts

Posted - 23 Jan 2014 :  12:32:35 PM  Show Profile  Reply with Quote
Jim Hand is flyin' with a flat tappet & Rhoads.Go figure.

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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 23 Jan 2014 :  1:52:58 PM  Show Profile  Reply with Quote
And I haven't heard of any lifter quality issues with Rhoads that have plagued other brands and been blamed (at least in part) for the many cam failures.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.
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cortcomp
Coyote

USA
5338 Posts

Posted - 23 Jan 2014 :  1:59:20 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I think the only complain about the rhoads was the ticking, but if you go with the largest XE cam you'd have that anyways. The smaller one i didn't have any. I'd hate to think what it would sound like on the street with the XE284 AND rhoads. But if you don't mind the solid lifter sound, i don't think anyone had any real complaints about them, performance or quality wise.
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keithnh
Tribal Scout

USA
14 Posts

Posted - 23 Jan 2014 :  2:47:53 PM  Show Profile  Reply with Quote
I was just thinking if you were building a motor planning to use them and wanting to extract the most they could give performance wise, what cam specs would you be looking for? Wish CC CamQuest had a box entry for "Rhoads" lifters with good information in it so you could see how various cams would be affected by them. I get that they give you more bottom with a top heavy cam, but there are quite a few cam selections as well as custom grinding available and choosing a cam is quite a science for most of us.
And most of us whether we want to admit it or not spend the majority of time driving on the street IN the rpm range that is boosted as well as made more fuel efficient by the action of the devices according to the posts I've read.

Keith
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Cobrabill
Talking Dog

Aruba
3128 Posts

Posted - 23 Jan 2014 :  4:02:19 PM  Show Profile  Reply with Quote
Also,something not mentioned here is that there are TWO flavors of Rhoads lifters.The latest version is supposed to be even "more gooder".

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bigD
Indian Spirit

USA
643 Posts

Posted - 23 Jan 2014 :  6:01:48 PM  Show Profile  Reply with Quote
quote:
Originally posted by keithnh

I was just thinking if you were building a motor planning to use them and wanting to extract the most they could give performance wise, what cam specs would you be looking for? Wish CC CamQuest had a box entry for "Rhoads" lifters with good information in it so you could see how various cams would be affected by them. I get that they give you more bottom with a top heavy cam, but there are quite a few cam selections as well as custom grinding available and choosing a cam is quite a science for most of us.
And most of us whether we want to admit it or not spend the majority of time driving on the street IN the rpm range that is boosted as well as made more fuel efficient by the action of the devices according to the posts I've read.



OK, I don't have any scientific evidence, but I can give you a country boy, old school rule of thumb. As stated, our 455's idled at 800rpm and left the line hard with the RA4 spec cam. And that was with 3.73 gears,a stock converter, a Q-jet, and 13" wide slicks. I can assure you they would lite up a set of hard street tires.

This combo pulled strong to 5000rpm, which is where we shifted. This sounds like the rpm range most street rides should operate in--800-5000. So I'd call this a good baseline. As ya'll know, the effective duration of the RA4 is approx 230 intake / 240 exhaust, with .470 lift. So there are some ballpark figures to use for a baseline. With a 455, using Rhoads lifters, I can see no reason to use a cam any smaller than the RA4. Yes, I know lots of guys badmouth the RA4, and label it as old school, outdated, and inferior to modern grinds. Well, I say show me the dyno results. And I've heard that some of the modern grinds, like the CC XE series can cause premature wear and and require more spring pressure to keep the lifter on the lobe, because they "slap" the valves open, and slam them shut. In other words they have a steep ramp.

As you increase the stall speed of your converter, you can increase cam duration above the RA4 specs, still have plenty of bottom end, and increased top end. The biggest cam I ever ran in one of these 455 bracket motors was a CC with 244 intake dur and 253 exhaust, with about .525 lift. It lowered our ET about .3 on a 1000ft track. On the street it would probably produce a lumpier idle and make power to about 5500rpm. Again these are just very rough estimates, but may help somebody, to serve as a starting point.

Edited by - bigD on 23 Jan 2014 6:06:17 PM
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Vid
Kicking Horse

USA
1685 Posts

Posted - 23 Jan 2014 :  7:08:20 PM  Show Profile  Reply with Quote
Whoa, whoa! Before you focus on the cam, be REALLY SURE about those pistons and your static compression at 9:1. If those are the common "budget rebuild" 8 valve relief pistons, be sure to **check the deck height***. Those pistons tend to sit .020 or .030 down in the hole, add to that (or should I say subtract) that large relief around the top edge of the piston, and your 9:1 just turned into a 7.9:1, even with those heads. If they look like the piston in the pic below, break out your measuring tools and get ready for some recalculating. Best of luck!

Edit: ((Blush)) oh this is from 2007, boy do I feel dumb. LOL

Edited by - Vid on 23 Jan 2014 7:15:58 PM
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Blued and Painted
Chief PONTIAC

USA
3407 Posts

Posted - 23 Jan 2014 :  8:29:50 PM  Show Profile  Reply with Quote
Keith, Sounds like your question is how much duration reduction do the Rhoads lifters provide at idle and low low RPM's. I think around 10 degrees if i recall correctly.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 23 Jan 2014 8:31:26 PM
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Chicagogoat
Cochise

USA
823 Posts

Posted - 23 Jan 2014 :  11:14:47 PM  Show Profile  Visit Chicagogoat's Homepage  Reply with Quote
Keith, if you want a max effort street engine with a Hyd flat tappet cam, then you must go with Rhoads V-max lifters, as Cobrabill mentioned. The V-max is their modern improved version of the original, it requires an adjustable valve train like any roller rocker upgrade with poly locks because you have to adjust the amount of lift reduction you want like lashing the valves on a solid cam believe it or not. It can reduce duration at idle up to 20 degrees according to the Rhoads site. These lifters are billed as higher reving, more vacuum, and better idle quality than their original lifter design for running even bigger cams.

So in my humble opinion, start with the best flowing heads you can afford as the center piece of your build. Build the short block with as much compression as possible for the street under 10:1 for iron, 10.6-10.8:1 for alum. Pick a cam up to 250 dur. @.050 and the lift you need depending on what your heads flow. If you want a max effort low cost flat tappet cam motor then a loud and rowdy cam is what's needed, but at least you can actually have a high reving cam and make it run low and midrange street duty.

I've been runnin the original Rhoads with a Lunati 282/294 voodoo cam on my 030 over 455 10.6:1CR with ported KRE d-ports. The cam has 241/249 duration @.050 and .560/.585 lift with 1.6 roller rockers. The idle is smoother than an XE284 I used to have and it revs quickly. Voodoo cams are supposed to have lobes that set the valve down slower for a quieter more reliable valvetrain.

Pure Pontiac: learn it, live it, love it!
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keithnh
Tribal Scout

USA
14 Posts

Posted - 23 Jan 2014 :  11:18:27 PM  Show Profile  Reply with Quote
Am home twiddling while out of work temporarily and probably obsessing a bit about cam selection. I dont know enough about it really ... trying to gather a bit here and there. I did read Jim Hands chapter "once" :) today concerning camshafts and see from the specs on the NOS aftermarket cams I have lift and duration are not the only cam specs ... lobe centers, lobe separation and both valves opening and closing events can have very different grinds for different reasons and be close to the same CC 280H and Crane 290H for instance. I did see today that Rhoads made a Chevy and a Ford cam kit but cant find the specs on them ... maybe a secret or something. Now am considering not buying a new cam until I draw out on graph paper the lobes of the best factory one and compare it to the one I buy by doing the same and superimposing so I can see the real under the curve differences. Jims book diagram is pretty cool and maybe some is sinking in. Now if I can understand what the Rhoads do and put that in there too Ill get a better understanding as well. He did say that the 9794041 cam he tested (RAIV cam) was very hard to beat for a hydraulic flat tappet and was noticably improved by the addition of rhoads lifters in his car. Good article on the net "Building a strong street machine" I think.

Keith
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rskram
Cochise

265 Posts

Posted - 23 Jan 2014 :  11:29:14 PM  Show Profile  Reply with Quote
I disagree with Cliff on this one which is not usually the case. I know that this thread is waaaay old but I started reading it and I can't help myself.

In the early 90's I drove an H.O. 350 in a '69 lemans with the 068 cam and #48 heads and 3:55 gears with a Muncie, and I drove it for 2 summers. Fun frickin' car! And you know what? That mother f**ker ran like a raped ape! I think an 068 cam is a hair to small for a 400, I would definitely go with 10-15 degrees more duration on a 114 deg lobe separation...you will not be disappointed.

So you bolt on a nice port matched and cleaned up dual plane factory intake or an RPM either one and some mildly ported and cleaned up factory heads and there you go! A really fun street car! Actually he could have went with a RAIV cam with those Rhoads lifters and I bet he would have LOVED the car.
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keithnh
Tribal Scout

USA
14 Posts

Posted - 24 Jan 2014 :  12:34:02 AM  Show Profile  Reply with Quote
Thanks for that info. Looking to find an excuse to slap my one wild and crazy Lunati into my creation to start ... Also had looked on Camquest and the best hydraulic cam for me appeared to be XE284, was looking at average TQ number and widest powerband. I do have a 280H which is still in the good choice list one notch lower rpm and a little less average TQ, it may end up in there teamed with the V-max in my 4.00 stroke 430CI on 3.00 mains. Will 0-deck and gasket unported 72cc #62's to 10.0. Noticed Jim cautioned about using Rhoads with too small a cam as it might cause higher dynamic CR to the point of detonation. Have a Victor but may overpower the heads, have an RPM too which might be right. Not sure about single plane and dual plane with the Rhoads??

9794041 .470/.470(1.5) 230/240@.050 for reference
I have
Lunati .425/.425(1.5) 256/262@.050
CC280H .480/.480(1.5) 230/230@.050

PS Hey what is the paint code on that wagon 2 posts back, very close to the color I want on my custom sportster and beautiful on the wagon.

Keith
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Vid
Kicking Horse

USA
1685 Posts

Posted - 24 Jan 2014 :  01:05:38 AM  Show Profile  Reply with Quote
Paint code is 1967 Pontiac "D", called Montreaux Blue. It's the original color for the wagon, but not the original paint. Thanks :)

Edited by - Vid on 24 Jan 2014 01:06:56 AM
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keithnh
Tribal Scout

USA
14 Posts

Posted - 24 Jan 2014 :  02:39:12 AM  Show Profile  Reply with Quote
Best friend in high school had 67 GTO Montego cream that was a memorable color too ... just the right amount of color to look natural and beautiful in my opinion. I like returning car to original color ... did so with my 84 Cutlass Asiatic and was very happy. Changed color paint jobs just dont turn out right IMO. My 64 Gto hope to return to sunfire red.

Keith
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Daywalker461
Tribal Scout

USA
5 Posts

Posted - 28 May 2017 :  8:09:43 PM  Show Profile  Reply with Quote
quote:
Originally posted by Cliff

The 60916 is a bit too much cam for the 9 to 1 400 engine. You would be much happier with a slightly smaller cam, closer to the specs of a stock 068 grind. You'd be much better off with a 214/224/112 grind, or something very close to those specs.

We like to see at least 10 to 1 static CR for the 60916, and at least a 2500rpm stall speed converter, FWIW....Cliff



Sir. Reference your below quote. How would this same set up run with an 068 cam. One step below 041. That's what I have with 72cc e heads un ported and a dished piston for 10:1. My builder loves the 068. I listened Should I replace


"For sure keep the 041 cam, the 2802 is a bit too small for the E-heads at 10 to 1 compression. We built/dyno'd a 455 with flat top pistons and unported 87cc Edelbrock heads using the Crower RAIV cam. That engine made 505hp/551tq and peak HP at 5100rpm's. "
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Blued and Painted
Chief PONTIAC

USA
3407 Posts

Posted - 29 May 2017 :  10:59:30 AM  Show Profile  Reply with Quote
The 068 and 041 are a mile apart when talking power range and drivability. Original post mentions 8 eyebrow pistons which sit low in the hole and are prone to detonation.
The 2802 is said by more than one to work well in the hi compression 400.
Tell us more about your combo or maybe start a new thread.
There are more came options available since this thread was started.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 29 May 2017 11:23:21 AM
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Steve C.
Crazy Horse

1675 Posts

Posted - 29 May 2017 :  12:17:36 PM  Show Profile  Reply with Quote
It is a 455 engine. Unported 72cc Edelbrock heads. Running a dished piston with a reported 10:1 compression. Street application, TKO 5 speed. For now that's all we know.
And it appears he is favoring 'old fashion' Pontiac factory cam technology

Until more is known we can open a catalog and throw darts.....


http://www.lunatipower.com/ProductGroup.aspx?id=287&cid=75

.

Edited by - Steve C. on 29 May 2017 12:24:13 PM
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Steve C.
Crazy Horse

1675 Posts

Posted - 29 May 2017 :  12:43:34 PM  Show Profile  Reply with Quote
From Comp Cams....

"Today, there are a huge number of aftermarket performance camshafts available. Your challenge: find the right one for your engine application. As you start to research the right cam for your engine, you'll need to take into account the application and vehicle. Other important details include the engine, transmission, rear gearing, fuel induction system, weight of the vehicle, type of vehicle and all the rest. As any knowledgeable technician can tell you, selecting a camshaft solely based on the fact that it fits your type of engine is a sure recipe for disaster."



.

Edited by - Steve C. on 29 May 2017 12:44:41 PM
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Steve C.
Crazy Horse

1675 Posts

Posted - 29 May 2017 :  1:02:09 PM  Show Profile  Reply with Quote
Similar combination to what Cliff mentions that you included in your post...

http://www.pontiacstreetperformance.com/psp/rebuild455MikeG.html

502 hp at 5300 rpm. However it uses unported KRE aluminium d-port heads. Similar but your Edelbrock heads are reported to have a bit more airflow and they have a larger intake runner volume. Keep that in mind.


.

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Steve C.
Crazy Horse

1675 Posts

Posted - 29 May 2017 :  1:19:10 PM  Show Profile  Reply with Quote
"My builder wants to put the 068 or similar grind Cam/Ram Air III cam in my 455"

"How would this same set up run with an 068 cam. That's what I have with 72cc e heads un ported and a dished piston for 10:1. My builder loves the 068. I listened Should I replace"

Maybe just me but I have some confusion here. Are you currently running a 068 cam or are you considering using it based on your engine builders suggestion ?


.
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Daywalker461
Tribal Scout

USA
5 Posts

Posted - 29 May 2017 :  2:41:24 PM  Show Profile  Reply with Quote
Builder ordered the 068 cam, sorry or confusion, if its not the right choice, I want to tell him to send it back
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Steve C.
Crazy Horse

1675 Posts

Posted - 29 May 2017 :  3:20:22 PM  Show Profile  Reply with Quote
"... if it's not the right choice, I want to tell him to send it back."

Hard to make an assessment until additional information is known.
It's already been suggested, tell us more about your combo and intended application and as mentioned I will also suggest starting a new thread on the subject taking into account ALL the information presented by Comp Cams that I suggested three posts ago. Read it.

Within your other related thread I already expressed my opinion the wide lobe separation on a factory 068 cam is too wide for the intended application and suggested a 110-112. And I suggested something with shorter seat timing and additional valve lift. Again my opinions, others may disagree and hopefully step up with their suggestions.


.


Edited by - Steve C. on 29 May 2017 3:25:29 PM
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Steve C.
Crazy Horse

1675 Posts

Posted - 30 May 2017 :  07:20:31 AM  Show Profile  Reply with Quote
"Dynoed a 455 tonight, numbers inside."

"Normally, I wouldn't put a cam this small in a 455, but customer wanted smooth, and torquey, so he gets it!"


http://www.pontiaczone.com/forum/showthread.php?t=30522&highlight=voodoo



.

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Steve C.
Crazy Horse

1675 Posts

Posted - 30 May 2017 :  07:54:17 AM  Show Profile  Reply with Quote
Now lets discuss valve lift. I've mentioned this before, and this information published by David Vizard might be of interest.

VALVE LIFT.

In part.... "A 2-valve cylinder head typically continues to flow more air up to lift values equal to as much as 0.35-0.4 times the valve diameter. The reason for this is that there is a flow pattern transition period that takes place at a lift value of about 0.25 of the valve's diameter. When this point is passed, if the port has been modified to support flow in this lift region, the valve efficiency actually starts to increase. This is the reason why a 2-valve engine responds to high lift."

"If you want to build a street motor with the most power without a sacrifice of idle and low speed qualities, then lift is the most important factor to maximize, not duration. The best street cams are those that seek to maximize valve lift while only adding a minimal amount of duration."

Bottom line, the engine wants all the lift it can and thrives on it, so run as much as mechanically achievable or not prohibitive to you because of cost and/or budget limitations (such as in a purchase for solid roller cam, longer valves to increase installed height, stronger springs, etc.). Obviously if it's a street application or race application will have a bearing on the situation, most here would be hesitant to run 0.700 lift on the street.

Now with the above information in mind let's consider that Edelbrock stock 72cc Pontiac heads are reported to flow 253 cfm at .400" valve lift and 272 cfm at .500" valve lift. Which in theory is going to be a better application with these flow numbers, 0.408" gross valve lift of a factory 068 cam or a cam with a higher lift such as 0.489". Or the latter cam with 0.538" using 1.65 rocker arms.


.
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pitts64
Sitting Bull

207 Posts

Posted - 31 Jul 2017 :  08:57:58 AM  Show Profile  Reply with Quote
quote:
Originally posted by Daywalker461

Builder ordered the 068 cam, sorry or confusion, if its not the right choice, I want to tell him to send it back



Your builder knows what he's doing!!

The 068 is as big as I would go in a Pontiac motor.. If you want high performance swap in a new Chevy L.S. motor..

No sense trying to get modern hi performance out of one of these old motors the new 6 cyls will blow you away let alone a new LS..

Never use Rhodes in any motor!! They will make it sound like it has ground up marbles in it, they give nothing but noise..

Edited by - pitts64 on 31 Jul 2017 08:59:53 AM
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cortcomp
Coyote

USA
5338 Posts

Posted - 31 Jul 2017 :  09:42:08 AM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I don't know about all that...i recall seeing one of the RAV vendors with a single carb NA setup putting down like 1200hp. The modern sixes are like 300hp stock? A warmed up pontiac should have no trouble with that based on cubes alone.
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Scott J
Buffalo

USA
61 Posts

Posted - 01 Sep 2017 :  8:33:06 PM  Show Profile  Reply with Quote
quote:
Originally posted by pitts64

quote:
Originally posted by Daywalker461

Builder ordered the 068 cam, sorry or confusion, if its not the right choice, I want to tell him to send it back



Your builder knows what he's doing!!

The 068 is as big as I would go in a Pontiac motor.. If you want high performance swap in a new Chevy L.S. motor..

No sense trying to get modern hi performance out of one of these old motors the new 6 cyls will blow you away let alone a new LS..

Never use Rhodes in any motor!! They will make it sound like it has ground up marbles in it, they give nothing but noise..



LOL, just LOL.
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Phil
The Great White Buffalo

USA
7219 Posts

Posted - 03 Sep 2017 :  09:53:01 AM  Show Profile  Reply with Quote
Gotta be satire from Pitts. And the LS commentary is even more hilarious than the 068. Btw, LS is a GM Corporate design and NOT a Chevy engine even though they'd love to take full credit for it.

Plus an 068 is practically a broomstick in a Pontiac. I've used it in a mild 350 and it might be good in a torque-mid range 400/heavier car situation but that's about it for me. There's just so many better choices with more (useable) lift.

Bowties are for Pee-wee Herman. "Chevy": even the name sounds cheap, but not as cheap as your Pontiac will be with an LS transplant.

Edited by - Phil on 03 Sep 2017 09:55:14 AM
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