dual exhaust on a 273
i u were going with a 3" pipe i would say you might have problems on the exhaust due to x-memeber! on my 318 in a 65 bcuda i went with 2in duals with a balance pipe. ran it right under my x-member on both sides. can't even see it on the car!
2.25 in would be the same thing. i like the 2 in and it sounds good at the back of the car and definitely not too loud. i used generic mufflers from my muffler shop.
i toyed with idea of a 2.5 inch single. the only reason i didn't was the tightness of my not correct 75 exhaust manifolds. DS is tight, necessitating 2 inch exhaust at least until it got out of the engine bay, i just went with it all the way.