The head comes bare.

Those are the sizes of the seat inserts.

It isn’t really a “unicorn” head.

It’s the same casting as a regular RPM head.
It has unfinished valve seats and the cnc’d port openings are omitted.
They are straight plug, and it gets the NHRA logo machined into the ends.

It’s up to the end user to make sure it meets all the pertinent criteria to make it suitable for use in the class it’ll be run in..... stock or SS.

If they were a simple “bolt on and go” deal in stock.......... everyone would be running them.