I wouldn't worry at all about using a stock exh. manny. As long as the exhaust system is free flowing enuff,(turbo muff etc.), it will still run better with the 2bbl. The 4bbl. might be a waste w/o a decent cam & head under it, the exhaust would be less important than those, ever see the contorted pipes on a Caddy Northstar? Ever ride in one? Obviously the head & intake flow is of greater importance, I'm all for headers & big pipes where one can put & need them, in Your case.....nada.....................................
