Family Fish on its 3rd life: 1967 F/B Resto

I took a day off work and played in the garage a little. The oil pan is on with nice new hardware. Next time I think I will spring for the one piece gasket, the 4 piece that came with the felpro gasket kit is a bit of a pain. The bolts are from alloyboltz (they sell on ebay and directly on their website) and are stainless steel allen head. Most of these will be painted with the engine, but I figured with the allen head I would have a chance at removing and replacing bolts without major paint disturbance.

The intake is on, and turns out one of the holes in the head is stripped. Dad is going to set me up with a heli-coil.

Does anyone know why these holes are in the head? casting relief? seems like a crud catcher, thinking about filling it in with something (jb weld, expanding foam?)

Test fitted the 90 degree oil filter holder with the header in place to check for orientation. Looks like no issues with the cast in numbers lined up to the line in the block. Now to figure out how all the gaskets work for this.

Thank you for following along,
-Chris