Cam swap without pulling motor

If you get a chance when you’re messing with the heads……..check what the difference in installed height is between the exhaust with the rotator, and the intake with the retainer.
I haven’t had a set of heads here with rotators on them in so long, I’ve forgotten how much difference there is.
The heads with rotators on them that I’ve worked on had exhaust valves with 2 grooves instead of the typical 4.