This is why you should port match your intake (pics)

I've seen guys with sb mopar port matched heads, take the rpm or M1 intake off, port match it and either LOSE e.t. or not gain anything! I've never dyno'd it that way, but this leads me to believe that unless the pushrod pinch is mostly removed, the intake being SMALLER than the port opening is the best it can be.
In other words, if the opening in the manifold is close to the AREA or SIZE of the pushrod pinch AREA or SIZE then any matching will be void.

Just what I've seen....

Oh, absolutely!!! Thats one of the reasons I collect every small port manifold I can, including the 22 degree marine single plane 4bbl. And also why I miss offenhauser. All their manifolds were smaller than the port. Or at least the ones I had got.

I have a Performer RPM here, bigger than the damn 4bbl gaskets, not exactly sure what good thats going to do me....... :angry7: