Valve to piston clearance?

FWIW, I worked out the pistons to valve clearance for the OP's combination at TDC; that is easy to figure since the .050" intake opening angle occurs right at TDC. I won't go over all the numbers (unless someone wants to see them), but basically, with that cam and that combination and using a 675 head as an example head, the valve-to-piston clearance is going to be in the .075-.085" range at TDC.

Since the valve is moving faster than the piston for the first 5 degrees or so past TDC, then that small clearance gap is going close up tighter after passing TDC. They might even touch. So it looks to me like eyebrows are 100% necessary here. They probably can be only .100" deep, but still needed.