Are you putting them in a K5? If you are they wont fit. Those headers are for IFS trucks. If you want power go, with long tube headers. Long tube headers make more power and torque than shortys. But if you want shortys.... Equal length shortys are a MAJOR PIA to change spark plugs. Some I have seen require the headers to be removed to change plugs. They really aren't worth the very slight gain in power over unequal IMHO.