Head Gasket .60 overbore

Most slant six head gaskets have a 3.500 bore. So this is not usually a problem. Sometime there is a problem, on the combustion chamber valve "relief", but usually not. Just lay the gasket on the block dowl pins, and check for alignment, then do the same on the head. I am told there is a Aussie made "permaseal" gasket that has a bore of 3.6xx.