The size of the engine won`t change the RPMs. I have 3.55`s with a 4-speed and it goes down the interstate with ease. I even raced a Bemmer looking thing up to about 125 and it was still pulling away strong. I drive the car all over the state and it cruzz`s awesome down the highway. A lower # ratio would get better millage, but who drives their classic GTO for gas millage??
