I was considering getting the hi po manifolds for my 72 318 till I read this just to confirm the passenger side exit was the same as my 318 lol. Thanks for the info guys.
The "bell" is larger on the 360/340 PS exhaust manifold, otherwise it comes out the same. I had an exhaust shop modify my Commando exhaust so I could use it with the 72 340 PS manifold. I'd run the your 318 manifolds. We put 72 340 manifolds on our 73 Dart, 318. Not much difference if you are running a decent set of dual exhaust and a relatively mild cam and 4 barrel carb.