I'm sure this topic has been discussed multiple times, but my searches produce no results. Maybe because I am using my phone and not a computer due to me just stroking the work day lately. That a story for another day. I have a 71 VC with a Rocket 350, I got the Thornton manifolds and stainless down pipes. But I cant seem to find any info about straight or offset mufflers for muffler placement and ease of tailpipe fabrication. Didn't find any premade tailpipes available besides someone saying the El Camino tailpipes fit but I think those are straight out the back and I will cruise with the tailgate window down.

 

I've been the one saying to use ElCo tail pipes because they do NOT exit straight out the back. The factory ones exit behind the rear tires. I used them on my 68 Vista. Of course, aftermarket ElCo pipes can go anywhere. FYI, dual exhaust was a factory option on Vistas with 455s. Note the 4800 cars with 455 in this parts book diagram. You can even see the factory part numbers for the Vista tail pipes (items 29 and 32).