O.k. guys I’m tiring to decide on what piston go with. I'm rebuilding 2000 c5 ls1. I have set stock 853 heads. I tiring to decide on witch way I want to go. I can go with stock 853 (66.67cc) heads and -11cc piston or having the bigger chamber 317 (71.06cc) heads and go with -4 flat tops piston. Witch is better combo for boost? Thanks for your help Guys.