main studs vs bolts

No, you need to use the 12pt nut ARP kit. Then for that position you trim the stud, leave off the washer, and grined the taper off the top of the nut. I've done this several times and sometimes the pump needs to be ground (still) to clear, but others it didnt... Same Melling pump every time...lol. Others I know just run the bolt in that spot but I never felt right about that.