Here's a video link to some videos of my 68 GTO and my brother's 69 GTO. My 68 has a 3" exhaust w/x-pipe and 3" Flowmaster Super 44's. My brother's Executioner 69 GTO has 3" pipes with an H-pipe and Super 44's with 3" tailpipes. The 505 on the dyno is in my brother's 69.
http://www.youtube.com/user/InsaneRi.../6/_0ieXhm5gKs