Due to the cant angle of the A-460 head's intake valve. the relief will most likely get into the top ring land of the piston over on the right hand side. We've seen A-460 pistons burn through there anyway because it is a thin area. For sure a C-460 piston, with it's higher ring placement will burn through over there. An exception would possibly be a C-460 piston that was designed for nitrous and they dropped the top ring down lower.
I hate to say this, but the best bet is either new pistons, or change to C-460 heads.