His car is a '73 so it's unlikely that he switched to small bolt pattern but couldn't this happen to the large pattern wheels too? I assume they use the same hardware.
the small bolt pattern uses 7/16 studs. the large uses 1/2" studs. i would check the lug washers though. the ones i had were about 1/8" too large of inside dia. for the lug shank. they were also very soft metal.
