Stock valve guide size X heads

As they come from the factory, SB Mopar heads have guide bosses with a nominal OD of .625”, and the guide bores are for valves with 3/8” stems.

After they have been thru the machine shop, and been set up with aftermarket parts to facilitate the use of a bigger cam……..who knows what the configuration is?
If it’s not noted in the paperwork, someone will have to check and see what was done.