1970 Duster with stock 225 slant six, factory style single exhaust but with a Thrush Turbo muffler installed. Factory exhaust manifold into 1 7/8 pipe to the muffler, exiting out the factory (1 3/4 or 1 5/8?) tail pipe.
YouTube- 225 Slant Six with Thrush Turbo Muffler - 1970 Plymouth Duster