Originally Posted by FUBU
Nice! According to me I think the difference cannot be that big. Coming from stock to new pulley yes, but from a 65 mm to a 63mm you will not be able to notice it. 0.05 in your 1/4 mile at the most. just my 0.02$
and you would be wrong!!
as the 65mm would be equal to a 178 mm crank pulley a 63 would be close to a 181 crank pulley without the overdriving issues, build me a 63mm s/c pulley and ill show you how well it works!!