I just realized that's a 70 Bumper, Did you custom cut the bumper to add the N-25? That's awesome, I was thinking of somehow converting mine to that.
V8 member Rusty Davenport will convert any 70-72 rear bumper to N25. http://v8buick.com/index.php?members/rusty-davenport.311/ He did mine as well.
Here is some additional data. MT super scavengers w 3 1/2 collectors into a 3 1/2 X-pipe into huge Scott Brown long case street mufflers into 3" tailpipes from Torque Tech. No discernible ET or mph difference to open headers. Very quiet when compared to a previous system that was much smaller with no X pipe and early dynomax mufflers. Motor is a fairly mild, ported stage 1 455 making 450-500 HP. The Torque Tech tailpipes fit extremely well, but yes, 2 1/2 would be more friendly under the car, and lighter. The big pipes up front don't tuck very well, so ground clearance could be better. Note the Scott Brown street mufflers haven't been made in years but they are AMAZING. Torque tech I think is also out of business. It's nor annoyingly loud, but when you get the revs up and are on it, it's wicked. The X pipe is a must in any serious system IMO. Something to consider with sound is pipe thickness. If using thinner wall SS, it will not damp certain frequencies as well as thicker aluminized steel. Good to know Pypes is so dedicated to good fitting systems.
