torque for old centerline wheels

Hi looking for the torque value for some old centerline drag wheels (spun alum., rivets on the face) I think they were like the original centerline wheels. anyway they are 15x3.5 SBP w 7/16" studs. Not sure what the torque should, but it's got to be more then the 15-20 ft/lbs they were torqued to when I took the off.

Thanks