HP on 302 - Team Camaro Tech
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post #1 of 12 (permalink) Old Mar 25th, 00, 04:58 AM Thread Starter
 
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Whats the true HorsePower for a chevy 302 that came in the 69 Z28???
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post #2 of 12 (permalink) Old Mar 25th, 00, 06:22 AM
 
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290
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post #3 of 12 (permalink) Old Mar 25th, 00, 11:17 AM
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290 is the factory rating for the 302. They didn't push the little mouse to its limits though (consumer/insurance issues)! The 302 will really rev and up around 7K I think it is pushing 400HP!! I have heard claims of higher and when I was younger I had a friend who shifted his @ 8K all the time!

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post #4 of 12 (permalink) Old Mar 25th, 00, 03:42 PM
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I dont think 400 is right, maybe more like 325-350. I had a stock 69 Z28, with L60 rear tires and 4:11s it would run low 14.00s. If you go to the pure stock musclecar drags you will see them running mid to high 14.00s all day. 400 hp would definetly be quicker that mid 14.00s. If you are talking STOCK Z28s.
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post #5 of 12 (permalink) Old Mar 25th, 00, 03:45 PM
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I looked up a couple of road tests, Z28's ran high 14.8-14.9 at 100-101.5mph. They were probably putting out about 325 horsepower.

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post #6 of 12 (permalink) Old Mar 25th, 00, 03:59 PM
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Got an old copy of Road and Track with a test done by Sam Posey. Had "dealer installed options" on car. 2x4, headers, etc. with the latest 60 series tires. Turned a 13.7 in the quarter. That should be solid 300 HP at rear wheels or about 350 flywheel. Peak ratings for those days would be higher probably, say 370-390. Radical little engine.
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post #7 of 12 (permalink) Old Mar 25th, 00, 05:41 PM
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In June of '67 the Wenzel brothers got their Z-28 to clock a [email protected] mph. This was in "B" stock class. The only mods allowed in that class back then was a cam change, headers and 7" wide slicks. They did this with 4.88 gears. That was their first trip to the track with their '67. Later that year they turned a [email protected] This car was setup with a single carb by the way! I know '69 was the orig. topic, I think it might have gotten a bit better (more reliable) by '69!

Stock 60 series tires in those days were less than desireable and I don't think would have allowed 7000+ rpm hole shots and speed shifts!

I think it was in "How to Hotrod a Small block" that I read the 302 has the highest horsepower to cid ratio potential of all the small block family (1.53hp per cid). I know that book was written in the mid 70's so their numbers may be a bit dated. It has indeed earned a place on the all star list in my book!

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[This message has been edited by DjD (edited 03-25-2000).]
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post #8 of 12 (permalink) Old Mar 26th, 00, 04:30 AM
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I dont think you can directly correlate 1320 times to hp with the 1st gen Z/28. Chevy never meant for this car to be a 1/4 mi screamer. It was built for SCCA Trans Am road racing and tended to be relatively weak off the line but would really start to move at higher rpms. 400+ hp could still be correct even with 14 sec 1/4s.

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post #9 of 12 (permalink) Old Mar 26th, 00, 04:08 PM
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The formula is based on MPH not ET. They are not precise but will give a ballpark. Everyone over estimates horsepower just like everyone over estimates how fast their car will run at the track. I think that 400 horsepower is not out of the question when open pipes are used since the stock exhaust is extremely restrictive.

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post #10 of 12 (permalink) Old Mar 26th, 00, 05:56 PM
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The 302 used all the same parts as the 327/365 Corvette except stroke. If you run these two engines on a dyno program they make almost the same horsepower, but at different rpm.
I've heard of a theory that the MAXIMUM potental horsepower of a normally aspirated engine is determinined by the valve area.
This assumes the intake to exhaust flow ratios are not out of balance, and the ports are not smaller than the valve, causing a restriction. And an optimum cam.
The theory states- "intake valve size determines peak horsepower, engine displacement determines the rpm that peak is reached.
Using this theory, a 302 compared to a 327 would have nearly the same peak horsepower due to using the same heads and cam. The only difference would be due to rod ratios, piston speed, and other friction loss.
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post #11 of 12 (permalink) Old Mar 26th, 00, 09:42 PM
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If you use the MPH at the end of a 1/4 mile to determine approxamate HP. I think you get aroun 300hp. This motor was probably rated at SAE Net HP rather than Gross HP which may be around 350. If you compare times from a 295 HP 350 it is a bit slower in the 1/4.
Does that sound about right guys?
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post #12 of 12 (permalink) Old Mar 29th, 00, 05:43 PM
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A very close friend of mine just restored a 69 Z and bluprinted the motor. He saw a peak horse of 414 horse at 7250.
But it didn't start to climb untill about 4500. I have had two Z cars, and the 1st was a 50k original mile machine, and it hauled, from about 3500 on up to about 7500.
The problem with 1/4 times, is that you almost have to get out and push, to get the car rolling from a dead stop, regardless of the gear, and coming out of the hole at 6500 rpm isn't going to do much for traction.
My car is a factory Z with some minor head work, factory cam, and manifolds. IT has a 750 Barry Grant on it , and it tears like crazy. 400 is obviously not out of the question.
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