Restrictive Mufflers

What "we" used to love were the original turbo mufflers. Now I'm NOT referring to what everybody (including Thrush) might be CALLING a turbo, but rather the original, factory spec'd, such as Walker/ Maremont replacements for turboe'd Corvairs.

The problem with the originals is the size of the fittings in some cases, but the really BIG problem is the pollution nowadays "everybody makes a turbo" so nobody knows what one really IS (was)