all i need is good mufflers.

Johnny Dart said
And actually all you need is a good muffler, not mufflers on a slant 6.

A single 2.25" - 2.50" exhaust with a free flowing muffler is all you need.

But hell, what do I know ?

Play through.

This is what I did as well. One single 3" (collector size) with the longest muffler that would fit.