Re: One More BB Question Please
If you replicate the scallops exactly you would have a blown head gasket on a a 454.
But you are correct grinding a bit in the location of the scallops on a 396 using a used (compressed) head gasket as a scribe line, it would enhance the low lift breathing capability of your big block. I do it as one of my little efforts at improving breathing.
The big block has canted valves that open in toward the center of the cylinder, but at low lift they are shrouded by the head and cylinder wall. Bigger the valve, the bigger the problem.