340 vs 360 confirmation

Would I be correct in assuming that any of the stock exhaust manifolds for an early 70s 340 will flow better than the mid 70s and late 70s 360 stock manifolds? I have a chance to pick up some 72 to 73 340 manifolds dirt cheap.

Since I'm building a daily driver I'm going to ditch these awful headers. I'm not saying all headers are awful, but the ones I currently own definitely are!

Thanks again folks.