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Old 03-12-2004, 07:09 PM
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Horsepower.... and horsepower loss

Power Question:
Okay, I have a 1979 Pontiac Trans Am (it had the 403 motor in it originally). Right now I have a 1968 Pontiac 400 out of a Gran Prix (the good motor) I also have the number 16 heads (again the good ones), and an Offenhauser low rise single barrel carb intake manifold. I am planning on building the motor from scratch with all new parts. My goal is to get around 400 to 450 hp and 400 to 450 lbft at the wheels, but the power has to go through a th-350 trans with the B&m transkit (and shift kit) and a rear end with Auburn gear posi unit and richmond 3.73 gears. How much engine horsepower am i going to need to get me to those numbers, and what percentage of power will i lose through the drive train? P.S. I want to keep the stock bore and stroke, that is very important to me.

Cam Question:
same car and all that from above but i want a cam that will give me awesome low and mid-range power but also a decent high-range. I would like to stay with a hydraulic flat-tappet lifter but with roller rockers. I found a few cams from the more common companies but i like to divert from the crowd so I looked at Isky and of course they were very impressive.

Any help with answering these three questions would be greatly appriciated I'm starting to get stressed out about hitting those numbers.

Thanks to everyone and anyone who can help me,

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Old 03-13-2004, 12:31 AM
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dont think you'll ever get that kind of hp to the rear wheels as you'ld have to have like 700+ at the flywheel.
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Old 03-13-2004, 01:40 AM
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No he would probably have to have around 550HP at the flywheel, maybe not even that much if he was going for 400-450. Some easy answers would be using a tranny which takes less power to turn, mainly a 200-4R, you can even view the read up on the hi performance TH200

Also just read a write up on royal purple lube freeing up alot of HP and torque, thats another thing to try.

Other than that, getting those numbers out of a regular hyd. cam engine would mean you'll have to bump up the compression a bit and use a more aggressive cam which will kill your low end.

But with out switching to a roller cam, or going toward a blower, it's hard to get to those numbers. My friends blown cobra only makes 380HP and 400ft lbs. at the wheel with a kenny bell attached.

If you wanted to gain back some low end power you could switch to a dual plane manifold at the sacrifice of a few top end numbers. Just an idea.
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Old 03-13-2004, 09:25 AM
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the Offenhauser intake is a dual plane manifold and it's going to be pushing about 10.5:1 to 11:1 compression
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