Been covered in the past:
Chevy Roller Rockers the stock 5/16” stud mounting is IMO fine as is for most street pressures and rpms. I’d research as much as possible on any reports on stud breakage with the 5/16”....likely not going to find any but you never know. And then if you did, what spring pressure, rpm, the geometry correct? You could go to 3/8” but I’d be checking how much cast pedestal material will remain on each pedestal before enlarging. 7/16 would be too big for the pedestal.
