1-5/8 versus 1- 3/4 headers

HawaiiDuster said
Unless your building a serious racecar, I don't think using the 1 5/8" headers will hurt your performance that much. Might even help out on the bottom end. Just about any type of header will do alot better than stock manifolds.

From everything I've read 1-5/8 will do better for a small cube mill unless you are doing all out racing sao I agree with HawiiDuster.