TTI Exhaust on a Duster anyone install one?

I am installing my TTI exhaust and the instructions for 67 to 76 A-bodies (might be off one way or the other but my 72 fit in there) say to remove the rear seat belt bolts and replace with provided #8 bolts ant install muffler brackets there. I did that and they are way off. Read further and it says may need to drill new holes on some applications. First of all, it's all I can do to read instructions at all, let-alone read ahead. :banghead: No biggie, anyone install and drill new holes for muffler mount brackets on there 70-72 Duster? The rear hangers are dead on.