I too have been involved with the sump studs... The thicker after market, SRM, alloy sump plates are supplied with hex socket screws to replace the OEM studs. Even drilling the heads and safety wiring I found this unsatisfactory. Luckily I found longer studs at my local auto parts store, 1/4" 20 threads at one end and 14" 28 on the other end. This allowed fitting nylock nuts for security. I've found the case holes to be open to the sump that allows oil to seep by the studs, but a dab of sealant on the case end of the stud takes care of that issue. "On n on we go".
BTW, for many years I've used readily available US 1/4" 20 SS socket head screws for primary covers, cam covers, etc. I don't build Goldies for dead accurate 'museum pieces'.
Last edited by dave - NV; 07/10/19 5:46 pm.