I have a 1991 Camaro Z28 305 TPI. It's stock and I can't figure out which power rating is the right one. I read that one was 205 hp and one was 230. So which one is the right one for my car?

Thanks for your help!

230

Thanks, I just can't figure out why they would have two ratings listed for the same motor.

not sure either, all the 91 z28's came stock 230 though

Yea I looked it up and some 305's came with "peanut cams" that dropped the horsepower so I'm pretty sure its not one of those lol

haha yea i never heard about those. pretty sure you have a normal 305

It could be something like a different cam grind or even different programming in the ECM.

By the time the fourth gen f-bodies came out, the GM engines were basically the same but the Corvette engine was listed as making more power than the Camaro however if both cars were put on a dyno, you could see they made the same power or the Camaro could possibly make more. The Corvette is simply listed as a higher number because that's GM's performance machine and can't be outpowered by a Camaro.

According to the TGO database, in 91 the Z28 with a 305 had 2 HP ratings of 205 and 230 however the 230 version didn't come with an automatic transmission and only came with 3.42 gears in the diff. The 205 HP version could have been an automatic or standard transmission with 3.08 gears for the standard and 2.73 with the automatic.

Providing everything is original, you can narrow down the engine rating solely based on the diff gears.

thats the only other thing that would make a difference. but ive never heard of that before. learn something new every day

I did some research and looked up my VIN number and I do have the 230 hp motor, but my rear end gears are 2.77s lol someone must've swapped the rearend out at one point.