In my opinion, you have a spectacular mis-match going on here. I don't see any way that those tiny little ports are gonna feed and excrete mixture efficiently with 435 cubic inches, no matter if they're ported 'til you see daylight. Get up off your wallet and get those Brodix heads I recommended.

What pistons are you using? Dish, flat-top, domed or what? What is the deck height of the motor? Whose cam are you using and what are the specs on it?