quote:

I did some Googling and there are some interesting discussions on the practice.

Theories include keeping the stud threads out of questionable threads in the bottom of the hole, allowing the stud to be torqued in good threads keeping it more square to the deck, and keeping the taper of the stud from contacting the deck.

Seems to be more common in aluminum block applications, for whatever reason. I’ve not experienced ARP studs with that feature in my BBC stuff.