I have a muffler shop 2 1/4" dual exhaust with what looks like flowmaster welded aluminum mufflers on my 73 318 Barracuda. Sounds great for a basically stock motor. If I build up the 318 or swap in a 340 I 'may' put headers on it, but I really like the mellower sound and stock look on this car. I have heard a lot of good things about accurate exhaust if you're keeping yours stock appearing, otherwise I'd also check out systems from TTI, magnaflow, etc.
Later, Jim