Quote Originally Posted by bluegtp91 View Post
Try swapping belts if you want, but basically...when you are flowing better you aren't making as high of boost numbers. All boost is...is a measure of restriction. These motors tend to run great around 8-12 psi....so it sounds like if you aren't knocking, try a 3.1" or even a 3.0". Might help get the boost numbers up a little...but too much boost is just going to heat soak that IC and cause more parasitic loss from the smaller pulley.

How's that?
Marvelous