40 lug nuts
+1Yes, they machine the stem to compensate for grinding the seat.
Kind of where I was going with that. You can mill the head down but can run into valve / piston clearance problems. To compensate, you have to machine the valve stem down or shorten the push rods. Even then, you may have to deck the pistons depending on how much the heads were milled.
The only place I know of to get heads is from Ford, but if you have someone on the inside, you might be able to get them for less than $1400/ea.