I was really curious so I went ahead and pulled it apart. Crankshaft is 1/2" diameter the entire bearing surface so while the rear bearing is much larger, both bearings are same 1/2" i.d.. Not sure what that means but I think it means it's not any version of a Combat Special. The piston and liner are ABC, bad news is the piston is scored in the front its entire height, inline with the wrist pin. There is a corresponding groove in the liner but it is small right at the edge of the transfer port. It has been smoothed out but the damage is done as far as that goes. I gambled $30 buying from a bad picture hoping I might get lucky, doesn't look like it this time. Thanks for the help, George