Yeah, something really isn't right. I have snapped a bunch of pictures and talked with my engine builder, who did the work on this head. The current hypothesis is that the SI Stainless valves I bought are too long. The installed heights are still visible in black marker on the cyl. head:
1.787" is a lot more than the specification paperwork from Iskenderian (1.700"):
The lash cap I pulled out with the one rocker arm I removed last night is .117" and about 3 tenths. Stock is .118".
But the "kit" I ordered from Iskenderian has .175" lash pads, (part LC175 - is .175" thick - I looked it up on their site):
The retainers currently installed look like the Isky ones. The depth to accommodate the lash pad is notable. Comparing to another exhaust valve which has not had the rocker and lash pad removed, the lash pad (I am assuming also .118"/stock) is "buried" in the retainer.
So, the theory right now is that SI Stainless valves are taller than the stock valves (4.620").
I think I will have to pull the head.
My engine builder is a great guy and he has provided me with so much value over the years. In this instance, I should have checked the wipe pattern before installed the head, but I did not.
As far as I can tell, no damage has been done. So, I think I have been fortunate here.