1965 Barracuda 273 rebuild...intake code?

I do have the new Accurate factory style single exhaust system for it and will go with that with the rear rectangle tip resonator.
good stuff
What would that entail?
Mr Gasket 1121G is the smallest bore and thinnest head gasket made unless you have one specially made by Cometic. Their multi layer steel are a bit thicker but they can make them in a smaller bore size which may save a .1 or so compression.