Been running low 10`s for years(soon to b 9` based on my 6.22 1/8th)and I run the hooker supercomp 2" od headers spinning to 7000+. These 470`s like rpm`s from what I`m seeing as long as the cam and heads are up to it and my solid roller is an isky .680-.660 lift and 275-280@ .050.