For those of you that don't already know, rocker arms from a Studebaker OHV six are the same as the V8 rockers. I picked up an assembly from a six in excellent condition for $5 and compared them to some V8 arms I already had.
The aftermarket ones are impossible to find, but 53 studebaker v8 ones fit... what year six cylinder ones will work
I would say that any year OHV six rocker works. Studebaker was frugal about parts interchangeability, so I doubt that they ever changed the rockers on their six just for the sake of change. Since the arms have casting numbers on them, just compare any prospects to a V8 rocker and see if they match up. I'll look at the casting number later and post it.