I run 1 3/4 inch Hooker Hustlers, but tubes 7 and 8 exit through the fender and meet up at the collector...so you have to do a little cutting. They also interfered with my low profile Milodon pan on the passenger side, thus resulting in hours of reshaping the pan with a hammer and blow torch....AND they hit my transmission pan on passenger side where the collector meet the primary tubes (just some minor dimpling there).....Soooooo, if I were to do it again I would probably go with tti's.