Common issue- lots of threads about this.
Basically, you have to lose the washer and spot grind the pump housing for clearance.
Some people have contacted ARP directly and requested their special low profile bolt- they are aware of the issue, but don't seem too anxious to correct their bolt kit.
Correct! ARP has instructions on the amount of clearance they like to see which is .060 (IIRC) in there instructions.
This what I did, a little of both. I ground down the head of the bolt a little bit and clearances the oil pump housing a little bit.
Loose the washer, that is also in the ARP instructions when you get the main stud kit.