I’m confident that heads that used rotators on the exhaust valves did not get springs with dampers(for either valve).
I’m also pretty sure the rotators wouldn’t be paired with 4 groove valves.
(The reason for the 4 grooves is to provide rotation)
My recollection is that the installed height for a 4 groove ex valve ends up slightly taller than the 2 groove ex valve(when checked on the same head with the same retainer).
I’ll look thru my stash to see if I have a two groove ex have kicking around.
If I do, I’ll do the measurement….just for some added “content”.
Edit- I don’t have a 2 groove ex valve on hand.
Can you check the coil bind height of that exhaust spring?
I’m curious to see how far from coil bind it was in operation.