I now have my heads installed and torqued down. I am curious as to why Ford instructs us to put thread sealant on the head bolts. I did follow this instruction but as far as I can tell, all the head bolt holes in the block are blind holes.
Unfortunately a lot of info in shop manuals aren't correct. The 223 I-6 needs sealant as the bolt holes go into the water jackets, the Y block engines don't, blind holes as you have seen.