I'm building a n/a Z6 mini-me with some mild mods. My c/r is going to be about 10.8:1 and I'm wondering about header selection. I've seen some 4-2-1, 2-piece headers with primary tube sizes of 1 5/8" and 1 3/4". Which size would be better for low to midrange torque? Or since we're only talking about 1/8" does it really matter? Appreciate any input. Thanks.

 

Bump

 

won't matter much, but the smaller diameter piping will give better low and midrange torque.