'69 Z/28 heads used pressed-in studs. If the heads are hot-tanked during a rebuild it seems to affect the press fit. If one of them lifted the back-yard repair involved drilling a hole through the stud & boss and inserting a steel pin. If the stud lifts again it will break off the stud boss.
I believe some older Corvettes used a plain threaded stud; the '70 LT-1 used a screw-in shoulder stud with a push rod guide plate. Requires hardened push rods.
Were I to rebuild a 302 today it would not have pressed-in studs.