Intake suggestions

well, you will lose some bottom end with that single plane. also, your heads have not seen any port/polish/gasket match work according to your post, so I would stick with the dual plane you have or go to a performer RPM dual plane. run a 1/2" open plenum spacer for heat soak issues as well as good flow at WOT. I'd go with a holley, demons run rich out of the box. they can be tuned, but it takes some finessing.