318 vs 340 exhaust manifolds

Crackedback, that is some excellent info. I'm building a 390 (318 stroker) and was wondering how my current exhaust (340 and magnum manifolds) would do. I hope to make 350 horses at least, I'm building a torque monster (nothing over 5800 RPM) so I guess I don't need super flow headers anyway.
To make things even more interesting, the manifolds I have on my 318 are 2 1/4" exit hole (I think the 340 is a little bigger) which is larger than the ones in the test you posted. So that makes things even better. After I saw this thread (just out of curiosity) I went outside and used a piece of .030" safety wire to fashion the shape of the entrance to the mag manifolds. Then I found a large washer that perfectly fit the wire. It came out just a hair under 1 5/8". I believe that is the standard diameter (1 5/8") for small block headers. now I haven't ported my heads 360 (596 castings) yet but I know for a fact I can get them well beyond 1 5/8" and blend the manifolds as well.
Who needs "stinking" expensive headers when your building a torque monster street machine??????


Treblig