You didn't say what engine your talking about, or what oil pump, or what studs(hex or 12 point).
I hope its a sbc. Got me curious as to what your talking about, so I mocked up some stuff to see for myself.
Glad I did. Found out that I need to drill some holes in my oil baffle, large enough to clear the hex nuts on my studs. Then again drilling holes in the baffle kind of defeats the purpose of a baffle doesn't it? Hmmm
I couldn't cause hex nut interference with a Melling "M55" or a "Select" oil pump.(see pics) Don't know if a high volume pump would be clear or not.
However I found out that I may have to either trim the stud, or clear/grind the neck of the Select pump by about .025". I know that some pumps have had issues with breaking at the neck, but the Select looks beefy enough that just a little sanding/buffing shouldn't do any harm. I don't feel comfortable cutting/grinding an ARP stud as the heat might weaken it? Besides its not exactly easy with ARP stuff as tough as it is.