rx7_fanatic

sounds like the PR's are a bit too long, and when swapping cams and going to longer PR's thats common to get a little valvetrain noise, but if it doesnt effect driveability then there is no reason to rip them out to replace them with slightly shorter ones. i dunno what the stock specs on the mustang cam is or thestock length of the PR's, buti would double check and make sure those lengths are compatible with your cam and springs, and just double check like everyone said, having that noise means your springs will wear out faster than normal but it shouldnt effect things negatively otherwise if im correct.