Cylinder head heat crossover?

[Mark Yacavone]

A little lead is good for it. LOL
I can't remember if there are 1 or 2 exh. passages up to the intake side, but you want them completely filled and separated so the headers scavenge correctly. I've done many, many sets that are out there, using molten aluminum.
Also you want to mill the exh . side until the center ports are completely divided. Either that, or build up a dam on you header flanges.