AJ1978TA

Ok, I am going to have to get a replacement crank/bearings for my car, long story, oil pump went too, but I am going to get a different cam while I'm at it. I have a stock 78 Pontiac 400 V8, estimated compression is about 8:1 I think, it says 6x on the head casting, I have headers and true dual exhaust, I will be getting an edelbrock intake/carb for this too. I see an edelbrock cam kit for the intake manifold (its the base performer, idle-5500 range), the lift says .420 int, .442 exh., duration is 204* at .050 int., and 214* exh at .050........Is this a decent cam to use? It sounds very small. Will it work? I need a cam that will give me decent power but I don't want to lose any torque. My other options I see here are the High Energy 252H, 260H, or the 268H. Is the 268H too big for my car? For the 260H, it has 212* duration @ .050 and .440 lift, the 268H is 218* @ .050 and .454 lift. I'm not sure what range of duration, etc the car needs to run at, so I'm just giving this info to you guys to try to help me along. I don't have a TC or anything yet, I believe gears are stock too. I basically want to run the largest possible cam without losing too much torque down low or just not functioning properly at all. Maybe later I will get gears and a TC, but that isn't definite. This is a daily driver. Thanks for any input!

[This message has been edited by AJ1978TA (edited June 12, 2002).]

Damon

Edelbrock's cams are kinda old school. Very lazy ramps, relatvely low lift.

If you want to build torque you want good "area under the curve" from a relatively short duration cam. Meaning you want to get the valve off the seat in a hurry and back down quickly without spending a lot of time at near-useless low lift conditions. Look at a Crane Energizer or a Comp Cams High Energy grind with about 210* duration @ .050. That'll work a bit better with a low compression motor than the Edlebrock cam. Real good mid-range punch.

I know that doesn't sound much differnet than the Edlebrock cams but if you compare the .050 duration to the "advertised" duration for each cam you'll see that the Edlebrock grinds spend a LOT of time hovering the valve just barely off the seat- bleeding away what little compression your motor has to begin with.

'Fer example:

THe Edelbrock cam has 204* of intake duration @ .050, BUT it takes 278* of advertised duration to achieve this.

The Comp Cams Energizer 252 has a nearly identical 206* of duration @ .050 but only requires 252* of advertised duration to achieve this. See the difference? The specs I have lsited are not really 100% comparable in reality, but it's close enough to illustrate the point and still hold true to fact.

Short duration, quick ramps. Maximum flow, minimum compression bleed-off. That would be my advice.




[This message has been edited by Damon (edited June 12, 2002).]

9T8W66

I have some experience with the Performer plus cam and the 268 high energy from Comp. 2 different motors, The one with the performer + cam was a stock rebuild with a performer intake and a 750 VSec holley th350 and 2.41 axle. This car(`79 T/A)ran strong and had excellent low and mid range torque but did suffer at the high end.
the 2nd car (`78 T/A) had the 268 Comp and mildly ported heads. With 2500 converter and 3.73 gears this car would hammer LT1 SS's and WS6's.
I would recomend the 268 high energy from Comp even with stock heads and gears it should work fine. A good recurve on the dist. will help out a lot if you retain the stock gears. Good Luck!

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NBM`98 Formula 6spd,Ram air hood, Hurst billet,FRA,EGR mod,cags delete, Flowmaster catback.

AJ1978TA

I really want to use the high energy 268H, maybe I will in fact go with it. I was considering the 260H before, because the specs are very different and maybe 268 is too big, but since I will have a good intake/carb and exhaust system, it might work. The duration @ .050 is 218* for the 268, as opposed to the 212* for the 260H. This might be cutting it close here. I think I will go with the 268, I will keep updating as this car goes along

Also, I have a sheet here of comp cams stuff, what about these dual energy and extreme energy cams? They have different * of duration for int. and exh., that seems wierd, but these cams might seem to big. Here is a chart:

http://www.compcams.com/catalog/204_205.html
Maybe still stick with 268H?

BTW, just wondering, how many hrs of labor is required to change the gearing? I would like to get at least 3.23's later, I think I have like 2.73 in here now, I know I have posi but am unsure of gears. 3.42 might be too big for me, I get bad mileage as it is, and the car has no topend from the start. Hmmm.....Thanks for the tips so far!

Damon

The Exreme WEnergy cams are even more aggressive than the High Energy cams- even quicker opening and closing of the valves. The one thing I can say about them is that they are noisier than any other hydraulic I have ever heard, short of a race hydraulic. They are also split duration cams with more exhaust lift and duration than intake. They probably work just fine, although I haven't used one yet.

The 268 Xtreme Energy is a much wilder cam than the 268 High Energy.

Putting in a set of gears doesn't take long unless you want to do it right. Physically bolting them in I could probably do in 2 hours. Setting them up correctly could take another 2 to do right, IF I had all the tools to do so (I don't). I usually have a trans shop do my gears.