For the bottom ball bearing, I just measured the inside and outside bearing dimensions. I then went to the local farm store and picked up a sealed roller bearing for about $5 and slid it on, I then put on the bottom hardware and clip. Easy, simple, cheap fix that is better than the original.
This is what I show W/O tilt
67-70 upper bowl bearing 7800269 (still good GM number)
67-68 lower bowl bearing (plastic?) 7800528 available NOS dealers only
67-68 lower shaft bearing 7802186,7804200,7806142 superceeded numbers. NOS dealers only