technically, these aren't ball stud rockers, they are a pedestal mount, and a carryover part from the old AMC 290-401 engines.

on my OEM mag heads, I could run about .530" lift before I started getting into keeper to seal clearance issues, but the GM 3.1/3.4 springs will coil bind well before that. anything over .480" at the valve, check real close with those springs.

if you're buying new springs, get some junkyard 2.2" retainers and hughes 1110 springs, that'll give you about .040" more lift capacity than the 3.1L springs/retainers. they have near identical spring rates, but the hughes will have another 40+ lbs of seat pressure.