DZ302 engine horsepower rating

[musclcar]

i know the DZ302 chevy engine shows 290 hp because i've seen numerous cars with this engine with the engine size decal on the air cleaner.but i remember somewhere reading that this engine was way underated in horsepower because of the feds.what is the actual horsepower these motors put out is it something like 400 hp or ?.i know you could ad on factory installed headers,cross-ram and the 493-512 mechanical cam from the dealer as options right. so does anyone know then actual factory flywheel horsepower i've got a bet going and hopefully i win thanks

[Jeff H]

I think the actual hp is around 325-350 hp. Same as the Boss 302 Mustang although they were rated at 290 as well.

[Mr. T]

Good post. I have thought about the "actual" horsepower for 69 Camaro's before. How about the other 69's, like the SS L48, L34, L35, L78, or even the COPO L72 or ZL1. What would be the actual horspower for these engines? I have heard many times that L72's and ZL1's were way underrated for hp.

Jeff, is that 325-350 hp for a stock DZ, or after the crossram and other dealer items have been added?

[Jeff H]

I've heard 325-350 from stock 302 engines. With some head work, 140 cam, crossram and headers Traco dyno'd it at 458 hp I think.

[musclcar]

is there any documentaion or any other info on these hp figures for the DZ302. i tried to explain this to a friend and he laughed into my face

[@wot]

i recently saw a dyno test on an l78 chevelle with 60-70,000 miles, all stock, and it pulled 331 horsepower at the rear wheels. if you consider a 25% loss through the drivetrain, it would gross at about 415HP. a fresh stock engine would do much better

[Stuart Adams]

Whatever the hp is, my Z never felt fast. Overrated IMO.

[@wot]

the feeling your looking for is torque. try a big block. your small block isn't coming to life untill you get above 4500 rpm, and is happier at 7,000.

[@wot]

just checked your profile. you know plenty about torque!

[JoeC]

NHRA "corrected" the factory HP rating on some cars. I think they rated the 302 at 380hp. You can look it up but you have to look up the old ratings because NHRA changed the ratings sometimes. One year they really hammered the rating on the 302 because it was winning too much.