I have not run a 340-360 port intake on a 318 port. But I do know what a head flows like with a large step in a runner. That's all I am going by, theory I guess. Even Chrysler put 360 heads on 318's with 4 bbls.
Chrysler also put 360 heads on the factory 4bbl 318's. Just grabbed the entire top end from the 360, cheap and easy. Too bad they didn't put a decent cam in too and some compression. I'm not saying the bigger port intake on a smaller port head is optimal, I am just saying it's better than the Streetmaster.
