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Steve C.
Crazy Horse

1675 Posts

Posted - 16 Aug 2013 :  1:59:13 PM  Show Profile  Reply with Quote
Brett Flynn's post on PY....


1968 Firebird / 3550 lbs race weight (In July)
trw 455, iron d-port heads/SD intake/q-jet, 9" tires 1.458 60ft
275*/276* Comp Solid Flat, and 1960 389 forged rods...i shift it at 5600, and traps at 5800

http://forums.performanceyears.com/forums/showthread.php?t=734930

Original Compression Ratio and New Compression Ratio
http://www.wallaceracing.com/hp-cr-chg.php


Edited by - Steve C. on 16 Aug 2013 3:33:09 PM
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 16 Aug 2013 :  3:01:35 PM  Show Profile  Reply with Quote
From the calculator
Your old Compression Ratio of 7.9 and HP of 220 is now calculated
as a Compression Ratio of 10.5 and 238.40 Horsepower

I dont think this includes a duration change.


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

Edited by - Blued and Painted on 16 Aug 2013 3:04:27 PM
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cortcomp
Coyote

USA
5335 Posts

Posted - 16 Aug 2013 :  4:30:00 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
You're talking like 9% from a super high to a super low ratio there. So lets dial in to where we're always bickering: should i rebuild my 400hp 10:1 motor to 9.5 because im worried about octane (justified worry or not ignored).

New hp 394 hp. Thats 1.5%? Thats assuming that calculator is correct also.

Im not trying to say anything negative about cliff or jim or people with verified builds making this or that numbers or whatnot, we are lucky to have these people and their experience here on this board and they are solid cornerstones of this place. I just cannot brook inaccurate statements, and prefer that people are accurate and precise when discussing these things because this is where the half truths and misunderstood facts start, especially since google indexes this forum so much better than others on the net, so when ppl google "how much hp lost lowering compression", they will likely end up here. Lets give them strait honest and accurate info, and help them with their pontiacs so they'll stay.
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cortcomp
Coyote

USA
5335 Posts

Posted - 16 Aug 2013 :  4:36:49 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
Steve:

thanks for that info, i'm not a racer, how is 3500 on race weight? light or heavy? Being in the 10's in a street car, i guess i just assumed you had to have 600HP, but that setup doesn't look like it? Also, he must have traction and setup dialed in perfectly. I'm just impressed with that setup, but again i know next to nothing about racing, maybe 10's are easier than i thought? And he's doing that with stock rods!!
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Steve C.
Crazy Horse

1675 Posts

Posted - 16 Aug 2013 :  10:32:34 PM  Show Profile  Reply with Quote
The first generation Firebird to many of us is not 'heavy'.

Cliff Ruggles Ventura with his old 455 combo and iron heads was a 3760 lbs race weight. My 2nd Gen Trans Am long ago with the prepped 412 cid combo and a bit lightened was probably pushing 3800+ lbs race weight, I thought it was a pig, and at that time the best I could muster with a built 412cid combo with race ported iron d-port heads, Performer RPM intake and a Holley carb was 11.45 et. Like Brent it had a 'big' 251 degree cam.... got to love it :)

Brent 'rocks'....not only a guitarist but a very accomplished drag racer:

http://www.youtube.com/watch?feature=player_embedded&v=9EUwV2lRC7o

If you look at his well prepped chassis set up with Cal Trac bars/ spring set up, converter choice, Moser axles with a spool and 4.10/4.33 gear selection it will lead to the key to his excellent track times.

It's all in the 60-ft !

Edited by - Steve C. on 16 Aug 2013 10:54:24 PM
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Cliff R
Cochise

USA
535 Posts

Posted - 17 Aug 2013 :  07:38:35 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote

"So, in conclusion, it always comes back to: CHOOSE YOUR CAM FOR YOUR COMPRESSION AND USE."

With all the good information out there, folks still continue to make very poor cam choices for these engines.

Part of my job here is not only to build carburetors exactly for the application, but to make sure the user has a good end result. Not a day goes by when I don't have to educate folks on cam selection.

Cam selection is based on CID, static compression ratio, type/octane of fuel to be used, and goal(s) for the engine/vehicle.

Folks still continue to buy into the BS that you can drop a point of two of compression from these engines, install a smaller cam, tighter LSA, whiz-bang lobe profiles, and make ALL the power back.

What you really do is end up with an engine that idles OK but a tad "rough", throws ALL of it's power at you early, "feels" really strong because of how "snappy" the engine is, but really yields lack-luster vehicle performance.

Here's a case in point, not a Pontiac, but a REAL experience with a recent customer.

Guy replaces his 307 Old's engine in a mid-80's 442 with a custom built 350 engine. He sought out great flowing heads, but the compression ratio was going to be over 10 to 1, so he goes bigger on the piston dish, being afraid of detonation. Once again the "brick wall" of 9.5 to 1 CR we keep reading about scared him bad enough he lowered it down to be in a safe zone. He then calls Lunati to supply a "custom" ground cam for his engine. They recommend a really small cam, around 260 advertised and 207 @ .050".

The little 350 idles dead smooth with just a "hint" of attitude, and roasts the tires to death on a quick full throttle start. It's super responsive, and he's happy as can be, thinking it's a solid low to mid 13 second ride with his 3.73 gears and 200-4R transmission.

I rode in the car several times, and thought it was a "turd", but never told him that. Sure, it absolutely annialates the tires on a full throttle start, but also has ZERO traction. When it did hook up, power ended very early in the rpm range.

So race day comes, he elected for me to drive the car as he has next to zero experience. First run, spins ALL the way thru low gear, finally hooks up going into second, and runs just over 60mph and 10 something ET (1/8th mile).

2nd run same exact thing.

3rd run I do a "John Force" burnout on his new BFG tires, and it hooks SOLID. Leaves about as hard as my Honda Trail 70 bit bike, and takes so long to get thru low gear I consider ordering a Big Mac and a Coke to consume before I get to the finish line. Car BARELY dips into the 9's, about the same MPH as the first two runs.

4th and 5th run about the same.

We throw in the towel and do the math, it's a solid 15 second car best case scenario, not the Honda Civic "killer" he thought he had built.

So where is all the power at? The owner estimated 350hp, shows about 200hp going by the ET/MPH calculator. He's just not getting it. Same car that does a nice burnout in a hard right hand turn leaving Dairy Queen is a complete TURD at the dragstrip, with PERFECT traction.

Low compression and "modern" cam choice just isn't cutting it. I see this same thing played out ALL THE TIME with these things.

His little 350 would have ran a full second better with another point of compression and a plain old Melling 214/224/112 cam in it. It would have idled just as good, made about the same power right off idle, then TONS more mid-range and top end charge, having more compression and larger cam in it.

That's just the way it works with these things. Very difficult to get around the basic laws of physics. Low compression engines with small cams with early intake closing points on tight LSA's are going to build up low end power, tighten up the power range, and pull it down to lower rpm's. They will "feel" really strong by the "seat of your pants", then come up short on vehicle performance on race day.....FWIW......Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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ledhed76
Cochise

USA
304 Posts

Posted - 17 Aug 2013 :  09:07:39 AM  Show Profile  Reply with Quote
so i guess for a street car, it is fine...you guys need to remember, everybody isn't going racing in these things...some people (such as myself) only worry about going fast from 0-80 mph, past that is really a wash....and i'm not talking about dumping the clutch at 3000rpm to get it moving....i want it to jump off the line from just above idle....so having more torque in a tighter power band down low is just fine with me....

Edited by - ledhed76 on 17 Aug 2013 09:09:15 AM
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mrryals
Tribal Scout

USA
11 Posts

Posted - 17 Aug 2013 :  09:34:27 AM  Show Profile  Reply with Quote
Comp cams valve springs 995-16 these are the springs they recommend for this cam. I had to use taller valve covers now due to the height of set up
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Steve C.
Crazy Horse

1675 Posts

Posted - 17 Aug 2013 :  11:03:30 AM  Show Profile  Reply with Quote
Curious...

What was your installed height for those 995 springs? And did you measure the spring pressure with the retainers installed at that specific installed height ?
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cortcomp
Coyote

USA
5335 Posts

Posted - 18 Aug 2013 :  5:38:14 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I thought we had read people had control issues with the 995 springs (although might have been the XE284 or the 996 springs)? Maybe he does have a legit spring issue?

When i had the 428/xe262 setup, it would rev to the moon. 6K no problem and quickly. Of course, i'm sure peak power was like 4800, but at least it would rev there. If you try to rev past 5300 in the setup i have now, it just won't (again, 99% sure i have the way wrong springs in there). So, that being said, can you rev to 6K or are you having issues getting there?

On the dyno, i'm sure no fuel or ignition issues came up?
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cortcomp
Coyote

USA
5335 Posts

Posted - 18 Aug 2013 :  5:58:35 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
"and make ALL the power back."

I don't think that's the case at all, unless people are building these setups with only information from the comp help line and no one that has built or tested one? i thought everyone had the understanding that if you were going to go the XE/9.5 comp route, that you'd make power lower, it wouldn't be revving and making power at huge RPMS, and that you'd be a little bit short of a high compression conventional setup. I never expected my 455 to break 450HP, and i believe i've done just that already, and may get 10-15 more out of it. And that's with the cheapest iron heads you can find, ram air headers (didn't like the hassle of regular headers), and an engine i have run on 87 gas with no issues (not that if i had to put 89 or 91 in all the time it would honestly make a difference.)

I mean, do you have people coming in thinking they're building an XE274/284 that's going to run 500HP? I don't think i've seen that on anyone's iron headed setup, i don't think anyone makes that claim, and i never believed i'd be making the power that your car is or Matts roller XE setup. I do feel i've gotten what i paid for already. The extra i'm going for is purely bonus and fixing small things that annoy me.
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Cliff R
Cochise

USA
535 Posts

Posted - 19 Aug 2013 :  07:15:14 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
What folks miss in this deal is that a decent 455 will already try to make ALL of it's power right off idle, and TONS of low and mid-range. It's a poor design from a racing standpoint. Doesn't mean you can't make one work well. Installing parts to make them better at what they already do best makes no sense to me. Tiny little cams on tight LSA's just pull the power down too low, and too much right off idle, making them very difficult to hook-up.

Add some compression, long duration cam on a wide LSA, decent flowing heads, and you'll LOVE the end result. It will idle fine, strong off idle power, broad/strong torque curve, and still have you planted in the seat well past 5000rpm's.

You really don't even need super-flowing heads on one. Late last year, days before Norwalk we "threw" a 455 together with unported (not even port matched) #46 heads from a 69 428. Grabbed a used Crower cam out from under the work bench, and off it went.

The engine went into an 81 Firebird with some DOT's and unknown converter off CL. 11.90's at 112mph right off the trailer in the hot/humid air at Norwalk!......Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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mrryals
Tribal Scout

USA
11 Posts

Posted - 19 Aug 2013 :  09:59:53 AM  Show Profile  Reply with Quote
Long weekend, Thanks again for all the posts, engine builder tested the springs, I now have longer push rods and valves. Need to get my build sheet for the exact info on everything. Kid getting ready to go back to college. 99 Saab getting my attention now.
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Steve C.
Crazy Horse

1675 Posts

Posted - 19 Aug 2013 :  12:37:35 PM  Show Profile  Reply with Quote
Ok, the engine builder measured the spring pressure.

I hope the specific pressure was noted and recorded. My suggestion would be to keep an eye on their pressure over time. I remember the member on PY that had used the 995 springs and after use they were down to about 95 lbs seat pressure if memory serves me right, and it was nosing over below 5000 rpm with his XE flat tappet cam, 4900 rpm I think. And important to note there have been others in previous conversations regarding these 995 springs with a similar situation. That said, as well as many that report no issues.

I will repeat myself, you lose enough spring pressure and the lifter loses contact on the lobe as the valve closes, if this is the situation .... and note this is important..... after time the springs will further deteriorate to the point it can cause issues other than nosing over at rpm. When people call it 'valve float', more often than not this is what happens.

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cortcomp
Coyote

USA
5335 Posts

Posted - 19 Aug 2013 :  1:25:29 PM  Show Profile  Visit cortcomp's Homepage  Reply with Quote
I would be willing to bet that, once the valvetrain gets sloppy, it goes downhill fast....i can't imagine them losing pressure and and just staying down where they settled, i would imagine everything being kind of loose at that point, and beating on the setup even more.
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Steve C.
Crazy Horse

1675 Posts

Posted - 19 Aug 2013 :  3:04:30 PM  Show Profile  Reply with Quote
In many cases the cam manufacturer's recommendations are what's needed.

But it depends on the manufacturer and the recommendation. If you look at companies like Comp Cams... 99% of the spring recommendations are generic at best. There's NO way the same spring will fit ALL of the possible cylinder heads out there, or the proposed performance levels anticipated and the conditions the specific combo is run under. And god only knows what info you'll get if you call their "Tech" guys. It's all about the valvetrain mass involved in each specific application. They have probably NO idea how heavy your valves, retainers, etc. are, and the information is generally not provided.

Edited by - Steve C. on 19 Aug 2013 3:06:39 PM
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Cliff R
Cochise

USA
535 Posts

Posted - 20 Aug 2013 :  08:51:52 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
There is probably a point of no return with opening/closing velocity with these things. Stronger springs would just be a "crutch" at that point. There are other items to consider in the deal as well, valve train geometry, weight of the parts above the cam lobe both before and after the rocker arm, etc.

Harold new this and he made sure to keep opening/closing velocity pretty much on par with stock factory camshafts, then get the valves moving quicker past that point, and stay within the limits and abilities of the stock diameter lifters. I have always liked the Ultradyne lobes, and have never observed or heard about any problems with them when it comes to this topic.

Several years ago I had a nice discussion with a very well known Buick engine builder. He told me that he tried the XE lobes when they were first introduced, and they failed miserably in the big Buick engines, even breaking rocker arms. The power went dead on dyno pulls right around 5000rpms no matter what spring pressure they used. He went back to the long/lazy cam grinds he'd been using, no other changes, and the engines revved fine to well past 5500rpm's and made the power he was expecting from them.

Keep in mind here that the Buick valve train is considerably different than what a Pontiac uses, so it's not an apples to apples comparison. What we can learn from these things, is that there can be troubles associated with super fast lobe profiles. This is why I avoid them here, and have stayed with proven camshafts, both flat and roller that we know work well with Pontiac applications.....Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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sixt8bird
Chief Many Horses

USA
1114 Posts

Posted - 20 Aug 2013 :  3:04:44 PM  Show Profile  Visit sixt8bird's Homepage  Reply with Quote
If you want more power and run power brakes , never overheat and haul ass. This is the Cam I have used and recommend it to everyone. I see no bitches whatsoever with this cam. It is everything for a 12.5 second car to a docile street car that rev's supper fast has power at every RPM etc. Nothing to complain about. A friend of mine had an old HC03 cam in his car and had a very very rough idle, over heated and made OK power but more on the top end. Once he changed to the 114 degree lobe separation and to this profile, his idle was better, his brakes worked better and he made more power throughout the RPMS. My dyno sheet showed the rear wheel torque at 460from 3000 and peaked at about 5400 at 472 but still was above 460 at 6200. This was with non ported heads. The HP was just over 400 but the torque is incredible. I burn the MT 275 60 15s off even when I drop it from drive to 1st at 20 mph!! Its a screamer. I love the 114 as it gives you a broader torque band which is great on the street. This is the Crane specs. I'm also running 1.65 Full roller rockers.
(CRANE H-288-2) 283951 2400-6000 duration at .50 226 234 288 296 114 Lift is .458 .473 with 1.5s .504 .520 with 1.65s. My compression is around 10:1
You cannot go wrong with this cam!!
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loosetappet
Sitting Bull

113 Posts

Posted - 19 Sep 2013 :  08:55:58 AM  Show Profile  Reply with Quote
quote:
Originally posted by sixt8bird

If you want more power and run power brakes , never overheat and haul ass. This is the Cam I have used and recommend it to everyone. I see no bitches whatsoever with this cam. It is everything for a 12.5 second car to a docile street car that rev's supper fast has power at every RPM etc. Nothing to complain about. A friend of mine had an old HC03 cam in his car and had a very very rough idle, over heated and made OK power but more on the top end. Once he changed to the 114 degree lobe separation and to this profile, his idle was better, his brakes worked better and he made more power throughout the RPMS. My dyno sheet showed the rear wheel torque at 460from 3000 and peaked at about 5400 at 472 but still was above 460 at 6200. This was with non ported heads. The HP was just over 400 but the torque is incredible. I burn the MT 275 60 15s off even when I drop it from drive to 1st at 20 mph!! Its a screamer. I love the 114 as it gives you a broader torque band which is great on the street. This is the Crane specs. I'm also running 1.65 Full roller rockers.
(CRANE H-288-2) 283951 2400-6000 duration at .50 226 234 288 296 114 Lift is .458 .473 with 1.5s .504 .520 with 1.65s. My compression is around 10:1
You cannot go wrong with this cam!!



Interesting that the Crane 283951 and the summit 2802 both have advertised duration very similar to the old "s" cam. Just curious, (in your experience) which of those two cams would make the most average power, all else being equal, in a 400/406 motor, 10:1 CR, M20, 3.42, 750 QJ, 1.5 rockers? Would there be any significant difference in drivability?

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Cliff R
Cochise

USA
535 Posts

Posted - 12 Nov 2013 :  08:00:17 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
Anti-XE or XE cam basher, etc, has NOTHING to do with what I post here.

I am one of the very few folks who actually dyno's our engines, then back up the numbers at the track. We've paid for dyno time and back to back tested camshafts, "old" grinds, "fast ramp" grinds, and roller cams, all in the same engine back to back with no other changes.

I also own, drive and race my car, and have been in the final rounds at Norwalk more than most folks who will read this. You don't get to that level building engines and pushing them out the door and relying totally on customer "feed-back" for results. Most customers seldom if ever race their cars, and when they do they don't have perfect traction, so they really don't test anything.

In any case, I do this for a living, and test EVERYTHING. Folks look WAY too much at static compression ratios these days, when the key to success is dynamic compression, combined with engine breathing potential, and how well the vehicle is set up to use the resulting engine power.

There have been scores of thread on these websites put up from folks who came up considerably short on expected engine power using the XE camshafts. When someone points it out, they are immediately dubbed an XE "cam basher". Just look at the results, the cams bash themselves. There are probably other things going on with most of the builds, as some folks just aren't paying as much close attention to detail as others.

I have my own theories as to why these particular camshafts cam hurt engine power. We see this more with factory heads than aftermarket. I would imagine that the flat chamber floors and 30 degree seats don't much care for all that quick valve action at low lifts. These heads were designed to have very good low lift numbers, and work effectively with low lift cams and slow ramps. Dropping the valves really hard and shoving them open quickly probably does very little to help out the situation, not to mention they shorten seat timing considerably (less duration). Comp also pulls the cams down on a tighter 110LSA.

I've NEVER liked that deal right to start with, as this degrades idle quality, reduces engine vacuum at low speeds, narrows up the power curve, and pulls the power curve down in the rpm range. You do end up with some "attitude" at idle, so you can still impress your friends at a local car cruise, and enough power will be on tap to do a decent burnout in a hard right hand turn when you leave the parking lot. So for most of the folks it's not really a big deal if you lowered your compression and installed a "whiz-bang" camshaft. Your car will still get you from point A to point B, it will run just fine, and you can still have years of enjoyment from it. Isn't that what the hobby is supposed to be all about anyhow?.....Cliff

If you can read this, thank a teacher. If you can read this in English, thank a Veteran.
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ledhed76
Cochise

USA
304 Posts

Posted - 12 Nov 2013 :  1:37:33 PM  Show Profile  Reply with Quote
quote:
Originally posted by Cliff R

enough power will be on tap to do a decent burnout in a hard right hand turn when you leave the parking lot.


Every time I do a rolling burnout from 20mph in a straight line with my XE262 cammed car I think about your dumb comment and laugh at the fact that no matter what my carb/engine needs were, I would never give you a dime of my money...
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Phil
The Great White Buffalo

USA
7216 Posts

Posted - 12 Nov 2013 :  5:12:46 PM  Show Profile  Reply with Quote
Ever since they started carrying Orange Julius at DQ I drive easy out of there.

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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Cliff R
Cochise

USA
535 Posts

Posted - 14 Dec 2013 :  07:05:11 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
On the subject of "burn outs" and traction.

Last summer I tried to help out a local guy with a 1986 Hurst Old's sporting a "350" HP 350 Oldsmobile build. It was one of those cars that would EASILY roast the tires in low gear from 20mph. He was using a "modern" whiz-bang camshaft in it, some "special" casting hand ported Old's heads, 200-4R trans, 3.73 8.5 diff, and had convinced himself that it was going to deep into the 13's if not high 12's at the track.

I rode in the car several times, and it was quite impressive in low gear, and PLENTY of power to easily overcome the tires and do impressive burnouts.

He enlisted me to race the car for him at the track, so we met up and did some runs with it.

The first run as expected it roasted the tires all the way thru first gear, and ran a less than impressive low 10 second 1/8th mile pass at 67mph. The next run was a blueprint of the first run. 3rd run I did a "John Force" burnout on his new T/A radials, and it didn't even squeak the tires on the launch. The car covered 60' about as fast as my John Deere riding mower, and ran a high 9 second 1/8th mile pass, no quicker in MPH than with no traction (high 15 second 1/4 mile). The next two runs were done in the same fashion, plenty of tire heating up and perfect traction. I actually thought about ordering a Big Mac and a Coke to consume on the way to the finish line, the car seemed to take FOREVER to get there.

After a less than impressive race day, I tried to help him out with improvements to the set-up to get some respectable numbers out of it, but instead he came up with a hat-full of excuses as to why it was so slow that particular day, including that the timing had slipped over 10 degrees and now that he had put it where it was supposed to be, it would pick up 2 seconds in the quarter mile and another 10mph or so. We never got the chance, as he got all pissed off at me for criticizing his fancy cam choice, among other things, so he's probably still out there impressive folks with his Dairy Queen burnouts, then getting outran from a stoplight by a Dodge Neon or Honda Civic with a "fart pipe" on it!......Cliff

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ledhed76
Cochise

USA
304 Posts

Posted - 14 Dec 2013 :  12:29:03 PM  Show Profile  Reply with Quote
So before you made fun of people whose cars couldn't do a burnout...now that criteria isn't valid anymore....make up your damn mind....
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Cliff R
Cochise

USA
535 Posts

Posted - 14 Dec 2013 :  2:05:02 PM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
Once again Winter certainly brings out the best in folks. Looks like I've got a new member to my fan club!....LOL....Cliff

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ledhed76
Cochise

USA
304 Posts

Posted - 14 Dec 2013 :  8:55:41 PM  Show Profile  Reply with Quote
Douche
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Blued and Painted
Chief PONTIAC

USA
3406 Posts

Posted - 15 Dec 2013 :  1:03:10 PM  Show Profile  Reply with Quote
Opinionated Douche? Maybe... Until you need a good accelerator pump or metering rods for a Qjet.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.
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Phil
The Great White Buffalo

USA
7216 Posts

Posted - 15 Dec 2013 :  10:06:36 PM  Show Profile  Reply with Quote
If I saw that Hurst Olds at the track I'd assume it was still the 307 Olds engine. And those are so bad even Monte SS's embarrass them.

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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Cliff R
Cochise

USA
535 Posts

Posted - 16 Dec 2013 :  07:36:20 AM  Show Profile  Visit Cliff R's Homepage  Reply with Quote
I don't think it ran any faster than the 307 engines they come with. I see this sort of thing ALL the time, since I do this for a living.

Folks buy into all this BS with aftermarket parts, and build these engines thinking they are making great power. Street testing is pretty much useless with these things, as traction is typically not very good, and even a 15 second car that spins the tires all the way thru low gear "feels" like it's going to do something when you get to the track with it.

The Old's mentioned here cam up at least 100hp short of where the owner/builder thought it would be. Here's a good link if you want to get an idea of how much power your engine really makes after an evening at the dragstrip:

http://www.dragtimes.com/da-density-altitude-calculator.php?elevationcorrect=1788&et=11.40&mph=119&correctetmph=Correct+ET+and+MPH

.......Cliff

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Sparafucile
Sitting Bull

158 Posts

Posted - 11 Oct 2014 :  01:12:10 AM  Show Profile  Reply with Quote
So let me see, what am I learning as a newbie:

On the one hand this guy is a damn fool for buying a whiz-bang cam because he didn't get the 7.4% more horsepower he was looking for.

Really? No one can think of a way to get him 8% more horsepower? I think Obama suggested checking you tire pressure. My $500 rims do that for me ( thanks NHTSA )

On the other hand, wasn't there a stock 428 rated at 390 supposedly understated hp? Is a crate engine in that model still available? What would one of those cost these days?

OK who am I to talk. I drive a Ford. ( insert sound of dying PacMan here )

I understand the passion. I loved my 290 HP 2 bbl.

Spara
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Phil
The Great White Buffalo

USA
7216 Posts

Posted - 11 Oct 2014 :  10:25:21 AM  Show Profile  Reply with Quote
That 390 hp 428 was rated (gross hp) differently as were all engines up to @ 1972. Compression going down in 71 got blamed for practically all of the hp drops but the blame should have been shared with the change in the hp rating system in 72.

Also, in the case of the "whiz bang" cams or whatever we want to call them this week, the power being thrown all into one place, whether 7.4% (or whatever difference) vs. being spread out over the power range adds up to a Hell of a lot of difference in overall performance. We don't race from one end of an intersection to the other (at least I don't) so I don't need the lions share of power concentrated like frozen orange juice into a tiny can.


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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