Vettelover8360

I have a 1991 L98 conv. and am trying to find my cheap horsepower. I installed a 3.54 gear, 2200 stall conv.,air foil,KN airfilter,open air cleaner, stock exhaust with gutted converter and LT1 mufflers. I am told fuel pressure is my next big gain for $100- would that be the next step? Also, how would find the code for which horse motor you would have in a 1991: 245 or 255 horse? :chevy

Vettelover8360

Also, is there a big gain going from 1.5 to 1.6 rocker arms? I am running the stock cam with no intentions of changing it. :chevy

HighHopes85

An adjustable fuel pressure regulator will help you out if you are able to do some tuning with it (i.e. timeslips or dyno). In a nutshell, your ECM will try to adjust fuel during mild throttle conditions based on what is in the EPROM (chip). However, under WOT, your computer stops making fuel trim adjustments.

So by using an AFPR, you will likely not notice any change during part throttle driving, but may pick up some gains at the top end. To confuse you a little more ;) some people get batter gains depending on how rich their car is if they lean the mixture out.

As far as the rocker arms, check with the manufacturer and listen to their recommendations regarding valve springs and if anything else needs to be changed. I slapped some on back in the day without worrying about this stuff and I feel that it has come back to haunt me. Good luck, -Matt-