H-Pipe Fabrication And Installation
Last week I fabricated and installed an h-pipe on my '71 big block. Knowing x-pipes aren't effective on C3's because of the distance from the engine they'd have to be mounted in I chose to install an h-pipe right behind my torque converter where it's as close to the engine as possible. I fabricated it using 5 angle-cut pieces of 2-1/2" tubing so it would have a 3/4" dropped center to miss the bottom of my new 2000 rpm stall speed torque converter.
An h-pipe or x-pipe will quiet the exhaust a bit as well as adding a bit of increased performance as they'll bleed off some of the pressure caused by the #8 and #5 cylinders firing only 90 degrees before the #4 and #7 cylinders.