273 commando Build

I would think minimum diameter would be the 3.975" spec?
**edit** obviously depending on bore size.
That is why you can't run a 3.625 bore gasket on a 273. You have to sandwich the gasket between 2 surfaces. Now put that gasket on to your head and see why you need that 3.95 dimension on a head gasket if your gasket fire ring is round.