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WKinne3
Tribal Scout

USA
11 Posts

Posted - 10 Feb 2020 :  05:48:18 AM  Show Profile  Reply with Quote
Cam Suggestions?

Looking for Cam suggestions, here is my engine setup:

400 Stock Crank, Rods, Pistons

#13 heads with the flow test results:
.100 int-88 ex-61
.200 int-159 ex-122
.300 int-201 ex-159
.400 int-227 ex-180
.500 int-232 ex-184

Comp 995-16 Springs, Ferrea Valves

1.65 Harland Roller Rockers

Performer RPM

HEI Supercoil Dizzy

Carb undecided

Long Tube Headers

TH350 w/ 3200 B&M Holeshot Converter

I'll have to look up my rear gear again but I'm not against changing it.

1979 Trans Am

I'm looking for something very stout on the street, I know I will have to mix gas, but I'm fine with that (there are 3 stations within 10 miles that sell race fuel here.) Not big into drag racing but wouldn't be opposed to making a run or two, but really want a serious street thumper. I was considering a Crower 60916 or 60919 but am open to suggestions. What cams would you suggest.


Corncob2061
Crazy Horse

USA
628 Posts

Posted - 10 Feb 2020 :  08:45:22 AM  Show Profile  Reply with Quote
The 13s have fair sized combustion chambers from the factory. They are called 72-75 cc heads but the run in the upper 70s stock. 76-78 cc is fairly common. If I recall this was on a 77 400 with the oem pistons. They have pretty small valve reliefs then have a bevel around the out side. If I recall correct the bevel is 3 cc and the valve releifs on those pistons are 4 cc. A lot of that era the pistons are around .015 from zero deck. Older 400s were closer to .020 down. Untouched using those numbers and a .042 thick gasket the compression is about 9.3 SCR. If the heads have been machined once it might be 9.5scr. You should be in a very reasonable range for pump gas.

The 60916 would be a great cam for this if it is below 9.5 scr.

Depending on where you look some suggest the 60919 is big for a 400, and the 60243 Crower works better in a 400. The 60919s I have checked were mainly bigger on the exhaust profile and only slightly bigger on the intake specs. I would suggest the 60243 over the 60919. Really should have at least 9.5 scr in a 400 for those two cams in a 400.

With the 3200 converter and head flow in the 230s with 9.2-9.5 scr, I personally would go bigger on the specs and pull the LSA in to 110. I would run a Ultradyne 288/296 and get it from Bullet racing cams. Lunati has the same cam off the self. The Compcams 280-AH10 would be my second choice. Very similar cam families the Ultradyne has a little more lift and a little gentler profile off the valve seat.

Edited by - Corncob2061 on 12 Feb 2020 2:37:59 PM
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WKinne3
Tribal Scout

USA
11 Posts

Posted - 10 Feb 2020 :  9:15:56 PM  Show Profile  Reply with Quote
My heads were CC'd at just under 72cc chambers, 71.888 or something simular. Does that change your suggestion at all?
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 11 Feb 2020 :  06:18:00 AM  Show Profile  Reply with Quote
That is great you know what cc the heads are and are not guessing. I come up with 9.98 SCR. Or 9.82 adding in the compression distance to the top ring. That does change the cam suggestions. Unless you plan to blend fuel I would stay away from the 60916 and run the 60243 of the 60919. The 60919 is a little friendlier for higher compression than the 60243. Could use either cam, I prefer the little bigger 60919 and use Rhoads Vpro or Vmax lifters. They are adjustable if you do not like the sowing machine noice you can tighten them down and make them quiet.

If you are going to run 1.65 rockers make sure you clearence the head on intake pushrod, the pushrod will hit the head with these cams I am suggesting.

Personally I would would one of the Ultradyne profiles. Either the Ultradyne 288/296, (.006 advertised is 282/290) 231/239, .485/.507 (.533/.557 with 1.65 rockers) Or the 280/288 (.006). 232/240 .50/.50 or .550/.550 with 1.65s. and have either Lunati or Bullet widen that cam out to 111 or 112 LSA. In a 400 with a 3200 stall I think I would set it at 111 lsa and 107 Icl and used the 280/288.

I had Bullet do a 112 LSA Ultradyne 280/288 (.006) 232/240 at .050 with 1.65 rocker, for us last year in a 455 with R/A manifolds and heads ported nearly identical to your 13s. Which is very similar to Lunati Voodoo 704 grinds (276/281 advertised, 281/289 at .006, 233/241 at .050) with less lift. Lunati Voodoo series has a little to much lift on the exhaust for 1.65 rockers I prefer the 280/288 Ultradyne. It does not need Rhoads lifters imo. Jay

Edited by - Corncob2061 on 11 Feb 2020 06:24:05 AM
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 11 Feb 2020 :  06:57:48 AM  Show Profile  Reply with Quote
Side by side comparisons with cams specs equivalents out at the valve with 1.65 rockers

Crower 60243 (symmetrical profile), 1.65 rockers with specs out at the valve
285/291, at .050 231/239, .527/.543

Crower 60919 with 1.65 Rockers. These are measured numbers I have taken from a couple 60919 cams I have done. Crower does not publish this, take it for what it is...

286/295, 235/244 at .050, .516/.516 lift. Symmetrical Profile

Utradyne 280/288. Asymmetric profile
With 1.65s
281/289, 236/244, .550/.550 lift

Utradyne 288/296. Asymmetrical profile with a little gentler acceleration than the 280/288
With 1.65s
283/291, 235/244, .534/.558 lift

The Ultradyne cams, because of the Asymmetrical profiles, will have better vaccuum and manors than what it would have in a symmetrical profile like the Crowers. Basically you can run a little bigger cam and keep similar street manors.

The Crowers are a little pricey. I can do a Custom Ultradyne for about the same price.




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Steve C.
Chief PONTIAC

2125 Posts

Posted - 11 Feb 2020 :  06:58:23 AM  Show Profile  Reply with Quote
Jay's response brings up a good point, many forget the volume between the top ring at top of the piston. Some of the high-tech calculators online call for it. Many (or most) do not.


.
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 11 Feb 2020 :  07:31:40 AM  Show Profile  Reply with Quote
I have been figuring the compression both ways lately, with and without that volume above the top ring. I question which way is really correct or has more value. Seems to me like the volume above the top ring volume would be effected some by end gas.


I am going to list these next cams with 1.5 rockers arms. The summit 2802 is probably the cheapest cam you could do. Advertsed as 282/292 224/234.with a 114 lsa. I think the actual .006 rating is closer to 286/296 to 290/300.

This might be the most value for modern higher compression Pontiac hft street cams right now. I have not ran it, but it is priced reasonable. It is the Howard cams 285/295, 230/240, .48/.47 lift with a 114 lsa. Can get it on a 108 lsa too.

https://www.summitracing.com/parts/hrs-410051-14/make/pontiac

About the only cam cheaper or comparible would be a melling ra4 SPC-8 cam. 292/303, 231/240, .469/.469. It has a ton of seat timing and it really needs Rhoads lifters in a 400, even in a 455 that came really response to Rhoads. I picked one up for $115 not to long ago.

FWIW, With long tube headers I would prefer to go no wider than a 112 lsa. Especially in a 400. Jay

Edited by - Corncob2061 on 11 Feb 2020 08:43:00 AM
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Steve C.
Chief PONTIAC

2125 Posts

Posted - 11 Feb 2020 :  09:20:52 AM  Show Profile  Reply with Quote
From one article regarding the volume between the top ring and the top of the piston... the measurement doesn't usually affect the final calculation significantly and is used only in very critical applications.

.

Edited by - Steve C. on 11 Feb 2020 09:21:14 AM
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WKinne3
Tribal Scout

USA
11 Posts

Posted - 11 Feb 2020 :  11:56:08 AM  Show Profile  Reply with Quote
Gentleman,
First off thank you so much for trying to walk my ignorant self through this. I have been doing some reading on Cam profiles and how different grinds respond, however I am still trying to figure it out and educate myself, so I apologize if my questions sound stupid. I appreciate you baring with me here.

So I do actually intend to mix fuel, even just for peace of mind, I don't want inaudible detonation when i am climbing in RPM's. I understand that I can get high compression managed with grinds that bleed off pressure, however this isn't efficient when higher in the RPM's. I figure for the purpose of this vehicle, Only a summer day weekend street rod, paying for better gas occasionally is just part of the deal. I own a boat, so spending money on fuel is nothing new to me hahaaha.

I'm also not strapped for cash, so price isnt a determining factor if I am sacrificing quality and performance. I would even consider a hydraulic roller cam, the price is more, but not too far out there for consideration. If a HFT is more likely to satisfy my desires for this car than I will go that route. I want to steer clear of Solid cams as I don't want to constantly be adjusting.

At this time I am leaning heavy to the 60919 or the 288/296 however I am curious what the behavior differences will be in these two cams and the recently suggested 280/288. It sounds as though I should have all of these ground with a 111 or 112 LSA. If possible could you do a basic lay mans comparison of these 3 cams? What would they do different that the driver would notice from the car?
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 11 Feb 2020 :  11:59:43 AM  Show Profile  Reply with Quote
I noticed this 13 headed 400 cam topic on Facebook Pontiac Racers. People sure are good at spending other peoples money. Just some random thoughts from somethings I read over on Facebook. In various posts, Comp 292 cam, E85, compcams 230/236 hyd roller, comp 276 hyd roller. 60919, (ram air 4 cam), different carbs, lastly a 242/248 solid cam. LOL, I like the last one, I am a solid cam guy on my own stuff... For fun which one of those do you want to look at closer? I am game...

I still like the Ultradyne 280/288 111lsa, 107 Icl as my first pick with 1.65s. Crower I still like the 60243 and the 60919, probably are better off with the 60243..not sure which compcams I would do, if you are going to blend the fuel I would use the 280ah10. It would be good to widen the lsa out a bit, but it might do OK.

The summit 2802 and 1.65s would work too. I am surprised it was not meantioned on Facebook. Budget friendly. That cam is cheap, can always go another direction later on the next build. Jay

Edited by - Corncob2061 on 11 Feb 2020 12:02:00 PM
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Steve C.
Chief PONTIAC

2125 Posts

Posted - 11 Feb 2020 :  12:53:33 PM  Show Profile  Reply with Quote
For conversation to inform. And despite the title it's similar for a solid flat tappet cam.

How Often To Adjust Valve Lash - Solid Roller for Street

https://www.stevesnovasite.com/threads/how-often-to-adjust-valve-lash-solid-roller-for-street.84738/
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 11 Feb 2020 :  1:08:52 PM  Show Profile  Reply with Quote
The gentler profiles do have their place. I would not necessarily steer clear of them. They do tend to last longer. I am well into the 10s scr on some of my cast iron headed engines. Even up into the lower elevens, on pump gas. Once the engine gets past the torque peak the air velocity over rides the aggressiveness of the cam you can make good power with the lazy cam profile and some extra compression. So long as the heads are suppling enough air, you can put a bigger cam and run higher compression and the higher compression engine will usually out perform the lower compression engine with the aggressive cam with less seat timing and the same .050 number. Or you can go more aggressive on the entire profile and add compression and gain power.

The problems for detonation occur with the aggressive cams building to much cylinder pressure generally at or before the torque peak. On pump gas a cam that is less aggressive and bleads off compression allows you to run higher compression on pump gas and make more top end power with the same bottom end torque.


If your going to blend gas anyway. I would do one of the 110 lsa cams and go bigger on the cam. But not a lot bigger. That 110 lsa will feel faster on the street and will come in harder against the stall. The engine will usually sound a little meaner to because of the extra cylinder pressure.

The Ultradyne 280/288 at the same 112 lsa will idle a little better than the 288/296, and it will make better power with the extra lift. Both those cams will make more power than the 60919 if they all have 1.65s. To get the 60919 cam to match up with those you need to move up to a 1.7 rocker arm. Then it would be a close, but the 60919 will idle a little worse. That is were the Rhoads lifters help the 60919.

The 60919 the ramps are the same on the opening and the closing, the Ultradyne are not, they open faster and close slower. It allows the engine to run a little more overlap and the cam idles a bit better than it would if it was a symmetric profile. In the end you end up with more power on the top end because the cam has more overlap, even though the idle was not effected.

The UD288/296 and the UD280/288 are pretty close in how they act. But the extra intake like of the 280/288 make more power if your heads will supply the air. It is a newer design of the 288/296. Both are good cams. So is the 60919.

Edited by - Corncob2061 on 11 Feb 2020 1:21:14 PM
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 11 Feb 2020 :  1:24:52 PM  Show Profile  Reply with Quote
The engines cylinder pressure needs to match up with the gas used. If the engine will run properly on 93 octane. Blending in race gas will make less power. I would shoot for one or the other. If your going to blend gas try to pick a cam that builds cylinder pressure.

Sorry for all the reading and long posts...LOL...Jay

Edited by - Corncob2061 on 11 Feb 2020 1:34:26 PM
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WKinne3
Tribal Scout

USA
11 Posts

Posted - 11 Feb 2020 :  2:00:21 PM  Show Profile  Reply with Quote
Jay,
You know more than I really understand obviously, but I am trying to pick up on this. I plan to mix gas only because I am not an expert on this stuff and figure that going higher than necessary octane is the safe route, even if i do sacrifice some power. I'd rather give up power than detonate and waste an engine. Lets say I still decide that mixing gas is the only way i sleep at night. If I follow correctly, the UD 280/288 with a 111 LSA is your cam of choice for my setup because it would allow me to bleed off enough pressure and run 93 while still performing a little stronger than the others, however the 280/288 with a 110LSA will pull a little harder but require mix gas because it doesn't bleed off as much pressure. 110LSA is going to have an agressive lopey idle while a 112LSA will have a smother idle, all other things being equal? I have the Max Power Pontiac Engine Book on it's way but trying to wrap my head around this as much as I can. I realize that it takes years of practice to understand this as well as you, but is there a place you would start reading as far as understanding Camshaft dynamics and how they affect an engines performance?
I'm still really gunshy about running straight 93 gas with 72cc heads, which tells me, I will probably mix gas even after those who know tell me I don't need to. I like the idea of the 110LSA, for two reasons, I like the lopey idle sound and I live in BFE so street manners are not as important as city driving, I also like that it will feel as if it pulls harder at midrange RPM's.
Thank you for finding that facebook post too, I was getting a million responses from a million people and it felt as if they all were telling me to use their favorite cam, vs. guiding me to one that will do what i am hoping it will do. I really appreciate your input here.
So, I know you have already said UD 280/288 111LSA 107LCL and I can run 93 octane, but would i be happier with the same cam and 110LSA if I WILL be mixing fuel?
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 11 Feb 2020 :  2:26:14 PM  Show Profile  Reply with Quote
If your plan is to mix fuel I would do a 110 lsa with the 280/288 UD. Or one of the 110 lsa cams like the comp 280a10. The lunati 276/284 has to much lift on the exhuast with 1.65 rockers, if you were running 1.5s or 1.6s I would steer you toward it. There is not a huge difference between the 111 and the 110 lsa. It just broadens the power out a little bit and would be slightly easier to tune. But on high octane fuel those 110lsa cams will shine. With the 1.65s on that 280/288 you should be able to run 93 in your 400 at 10SCR anyway if your in the upper Midwest. Lunati has the 288/296 at a 110 lsa off the self. If would be nearly as good as the 280/288. The 280/288 is a newer profile and is hard to beat with 1.65 rocker arms in a hyd flat tappet cam. .550/.550 lift is more than a lot of street hydrualic roller cams offer with 1.5s in that same duration at .050. Jay


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Steve C.
Chief PONTIAC

2125 Posts

Posted - 11 Feb 2020 :  2:26:15 PM  Show Profile  Reply with Quote
Right here on this site is interesting reading to start with...

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

And a Google search will turn up a lot of good basic material...

https://www.hotrod.com/articles/camshaft-basic/

https://www.dragzine.com/tech-stories/camshaft-101-the-history-and-substance-of-camshafts/

https://www.hotrod.com/articles/ccrp-9812-secrets-of-camshaft-power/

https://www.tildentechnologies.com/Cams/index.html


http://www.mondello.com/page28.html

And a fwiw, I agree with Jay's sentiments toward Bullet Racing Cams. The last two custom cams I have used came from them, both UltraDyne lobes. And many years ago UltraDyne lobes direct from Harold Brookshire when he operated the company. Have Jay order it or if you deal with them direct talk with Tim.



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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 12 Feb 2020 :  12:23:22 PM  Show Profile  Reply with Quote
The Tilden link Steve posted has a lot of in-depth cam theory in it. The Chevelles forum has old posts from UDHarold (Ultradyne) and CamKing(Jones cams) that have a lot of info. Speed talk would be the other forum that cam design details are mentioned at results in interesting searches.

Here is a old writing by Harvey Crane is a pretty brief well written doc on cam design and terms

http://www.4secondsflat.com/Cam_Design.html


FWIW..It is probably a little cheaper to go through me to get a Bullet cam than direct. But the folks at Bullet are great to talk to and they do cams direct all the time. Tim is on the dial by phone directory. Or my number is 402-682-1663 call or text..I mainly use Bullet on custom cams. They are super busy this time of the year. Worth the wait if you can wait. Most of the year they are super speedy. Cam companies can have some lead time here in Jan and Feb on orders it is their busy season. I do cams for fun, I do not have a pony in the race when it comes to brands. :).

Here is the compcams 280ah10 from summit, I was kind of surprised, it is a little pricey. Over $200. Surely it can be found cheaper at other suppliers? It may not be a stocked item, it is likely ground on order.

https://www.summitracing.com/parts/cca-51-314-4

I had not looked at its specs for awhile, it matches up with the UD280/288 fairly close on duration with less lift (.529/.529) versus .550/.550 on the UD with 1.65s. It may actually be the best overall fit for your combo with the 13 heads and the max flow that appears go for turbulent at a little over .5 lift. The 280ah10 uses magnum profiles somewhat similar to the UD profile. They have a little more velocity off and on the valve seat coming off the base circle than a UD. I still prefer the UD, I think the UD grinds and Crower grinds make a little less valve terrain noise. Jay






Edited by - Corncob2061 on 12 Feb 2020 3:46:39 PM
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WKinne3
Tribal Scout

USA
11 Posts

Posted - 13 Feb 2020 :  09:50:59 AM  Show Profile  Reply with Quote
Jay,
I think you have talked me into it, I am going to give the UD 280/288 a try. I'll gladly order from Bullet through you. How do we facilitate that? I'm not in a rush so this spring would be fine. let me know what we need to do to get the ball rolling on this. Thank you for all of your help, and I hope you get to pocket a little money on the Cam sale!
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 13 Feb 2020 :  4:48:03 PM  Show Profile  Reply with Quote
I can certainly get it ground if you want to go that direction. Basically you pay me via either a postal money order, or PayPal. Or just mail a personal or business check to our company (Cobco mfg inc) is fine too if your not in a rush. I have Bullet grind it and it gets charged to our account at Bullet, and it gets shipped direct to you. Can email through the contact link is on this site, call or text 402-682-1663.

I usually just have it direct shipped unless someone wants me to check the cam out, or do some cam indexing..


.. Jay

Edited by - Corncob2061 on 13 Feb 2020 5:04:38 PM
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WKinne3
Tribal Scout

USA
11 Posts

Posted - 13 Feb 2020 :  8:17:04 PM  Show Profile  Reply with Quote
I would most likely prefer paypal. I will give you a call tomorrow or this weekend if that is ok..

Edited by - WKinne3 on 13 Feb 2020 9:14:36 PM
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Corncob2061
Crazy Horse

USA
628 Posts

Posted - 13 Feb 2020 :  9:55:14 PM  Show Profile  Reply with Quote
Sounds great.
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