Octane
Dave14 said:
My friend just bought a 96 GT with 30,000miles on it. The previous owner said he has never run anything other than 91 octane. Is this necessary?

Does it actually add any HP? I was told that it didnt make a difference on lower compression engines.
Thanks
First of all 30K miles on a 96 GT is super low mileage
your lucky you have such a young engine it is probaly less prone to
detonation/pinging.A good rule of thumb is to run the lowest octane
possible without detonation/pinging!If you aren't running a power adder
or have your timming advanced I don't see why you wouldn't run 87
octane

At the most I would run mid-grade 89 octane because
91 octane burns so,slow it mite hurt performance.Also I have a 96 GT
just like you Dave and I have always ran 89 octane(mid-grade).When
I first bought my 96 GT I ran 87 octane and for some reason my stang
didn't run good.At higher rpm's I could hear a very slight pinging coming
from the bottom end so,I ran 89 octane in my 96 GT and the very slight
pinging went away so,as long as I own my 96 GT I will run 89 Octane in
it.Also I only run the best gas Chevron or Texaco! I never once got a
bad tank of gas from them that's why I only run Chevron/Texaco! Don't
get gas at a gas station if you see the gas trucks because you can get
a bad tank of gas.Good Luck!