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I have a mystery regarding the action of exhaust valves with the original valve stem keepers and associated parts. My valve parts are exactly as shown in the repair manual.

So this is what I observed after setting the valve lash at .0016:

When the exhaust valves were engaged by the tappets and the valve head lifted from the seat you could pull up on the valve for 1/8” or so. There was no noticeable side to side movement as the valve guides were replaced and seats lapped.

I am trying to verify if there should be the vertical ‘slop’ that is present in exhaust valves. It seems that the valve train would clatter around more than normal.

The lash caps do allow some movement so they are loose and free to rotate, the theory being that they will wear less if they do. I didn't think it was 1/8th inch though.
I do not use the lash caps; I always rebuild them like WW2, and later CJ valves, without them. I do not think they were necessary and aren't for me.
I can't find any new exhaust valves anyway, that take the rotator caps; they are different than the standard valves.