[71OLDS]

another vote for DynoMax Mufflers. I have them on my 468 Olds motor in my 71 442 with 3" pipes and they are fairly quiet until you go WOT. Here's the details including the part #s on the mufflers:

Hooker SuperComp Jet Hot coated 1 7/8" tubes, 3 1/2" collectors, into a 3 1/2” down to 3” reducer, into a 3” X crossover, into 3” in Dynomax Ultra Flow welded Mufflers(17229), into 3” tail pipes, into 3” Olds trumpets