I'm working on a buddies 340 motor. He picked up some edelbrock SB heads cheap but not the 340 specific ones and sure enough he's got pistons that hit with an .039' gasket.

I'm guessing the only solution other than trading for the right heads (or pistons) would be to set the heads on a mill and cut an open chamber to clear. I'm guessing this is all Edelbrock does? They "make" a 340 head by just milling a std head?

If so, what would I want to shoot for for quench?