Marine 273 build

I don't know the true story on the head gasket bore size. I bought an old Felpro gasket set off ebay that was for a 273 only, according to the label (assume it pre-dated the 318 LA). However, the bores were the same >4" D as today's gaskets. I posted a few years ago w/ photos. I recall that others said the original factory gaskets did have the correct bore size. Of course, someone could have swapped gaskets in the kit since the box was opened.