Why would you NOT run a complete OEM stock exhaust system for a A-body of the years that match your Exhaust Manifolds? Including stock OEM Mufflers? They ran GREAT when they were new and totally stock and sounded much better than the 'rattle-crackle' small block Chebby garbage.
How do I know? I'm an OLD PERSON, and I actually HAD a new one.
Bruce