I have a large stack 60SP, serial no. 078211. The crankshaft bush extends back into the front housing recess where the ball thrust bearing goes on my other samples. This looks original, not a mod. On the shaft is one of the dished washers used in the ball bearing, plus a thin shim with a larger ID. There isn't room to fit the complete 3-part ballrace, or needle rollers like the 60 Custom, and it doesn't look as though the late type roller bearing with 11 rollers in a cage would fit either.
Does anyone recognise this and what should be in there?
Barrie