Single vs Dual Plane, big difference?

I seriously doubt that 750 is going to work well on that 318. I have a stock-ish 318 in my Challenger, it was even happier with a 600 than it was with a 650, both Carter's. It does have an interesting intake on it though, I've got an old Edelbrock StreetMaster on it. Single plane, but small ports. I'm sure it would probably do better with an air-gap or probably even a performer, especially with some port matching.