Exhaust Manifold Application Question

Regular 340 or 360 A body manifolds would be better the later ones 73 and up are somewhat cheaper. But you won't loose much on a mild street motor either way. Check out Mopar Muscle test of exhaust.http://www.moparmusclemagazine.com/techarticles/155_0307_mopar_crate_engine_exhaust/index.html

With a 300 HP crate motor open exhaust the 318 manifolds made 311 HP the rare 340 HP units made 315. Now this was with open exhaust 24" head pipes. Looks the rest of the exhaust system is a better place to look for gains. Of course with a real hot motor the better parts would show more gains but good TTI street headers only made 327 HP 16 over the lowly 318 parts. I was going to install headers on my 73 Dart with a mild 318 till I saw this and am now re-thinking.