[Alan Roehrich]

Tim is correct, you can remove at least part of the center divider. However, if what you have is 12363420, it is probably real close, if not the same manifold, as an Edelbrock Performer RPM oval port. The divider is already pretty low, you may not gain much, because there is little if any to be gained by removing more divider. There is a version that is the same manifold, except it is CNC matched to the heads you run. You might also try various spacers if they are legal. Those castings are usually pretty clean, and the plenum is usually pretty good as well. The best gains other than a spacer are usually had with getting the fit and alignment as close to perfect as you can, and then working on getting the mixture distribution worked out.