Power loss. 318 Vs 340 manifolds

This is an interesting thread as I have been debating the same thing.

Not to hijack but are the hp manifolds from say a '68 dart the same from a '71 cuda? Meaning regardless of car will they all bolt up to any small block in any model wheather a,b,e body?

I have a mild 9:1 318 with 340 cam, edelbrock 4-barrel and intake. I have been reading that the cam choice makes a big difference in both manifolds. Would the hp manifolds help more with a 340 cam than a stock 318 cam or any other cam? Being thats the cam the 340 cars came from the factory with.