I just lined up the gaskets on the heads & checked the allignment, then i layed them over on that side of the intake & checked there, it looked pretty good, now how well you center the intake on the head is another story when you button it up lol. On my BBs, i check the upper & underside F&R of the runners with a feeler gauge, but thats hard to do on the SB intake.
I can't speak for the Iron Ram heads (i'm running RHSs), even though the runners seem alittle smaller on the crosswind, the allignment wasn't bad, now i also noticed in your article on this intake you were useing a cork gasket like an LA one, my Magnum gaskets were alot different then the ones you posted, i bought the felpro magnum head set FEL HS9898PT1 & those intake gaskets were nice, had a film coating & rings around the ports, not just a flat peice of cork, did you slot a set of LA intake gaskets to fit the Magnum heads?