Put a set of mid-70's Cadillac mufflers on it. They're 2 1/2" diameter, inlet and outlet, and one muffler is sized to flow up to a 500 cubic inch engine. A set of duals with those pipes and mufflers will handle a 350 at any RPM you want to run with flow to spare. They're quiet, too!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!