Thanks Cab

I tried the new ones on with the v-spring on the head, just to see what would happen, and they "sunk" well below the retainer top surface. They are 7 degrees, single grove for an 11/32" stem.

I am now wondering if the explanation for this confusion is that the heads were bought through a reputable engine builder and they perhaps switched to 10 degree retainers since the heads were intended for a race motor. Any thoughts?

Ragnar in Iceland