I just bought a 2017 mustang Roush Stage lll. I am looking to upgrade to the phase 2 kit from Roush which rates the HP gain to 727. My question is this, is the 80mm pulley that comes with this kit the best route to go or could I go even smaller to gain more boost?

http://www.americanmuscle.com/roush-...lue&GID=390770

 

Welcome to the forum.

I'd check out the Tech section for this question. The one specific to your year Mustang. Or there is on section devoted to the specialty cars like Roush, etc. But that ones not as busy.

Good luck