Does anyone know if the stock head bolt washers are the same size as the washers that come with ARPs studs? I got a set of ARPs a long time back and can now only locate one of the washers.

Turns out that the ARP washers are .005 of an inch thicker than the stock washers. 1/200th of an inch seems close enough to me. The full diameter and the center hole are off by a few thousandths of an inch as well but should still center up nicely once dropped on the head.