The fellow in the link below had a part made of unobtainium that I needed several years ago. Hopefully he can help you. Cal McCollum

http://www.vintagechevroletparts.com/

 Now there's an alloy I was not familiar with... thanks also for the lead.

From  a post by Chev Nut: ."The 600119 fits 1932-35 B.CA,DA. and F."   Try an ad in the parts wanted forum. 

@steve-d 

Thanks for your reply.  I found the source of the damage to speedometer gear!  The center bolt holding the front of the u-joint to the transmission output shaft backed out allowing the u-joint to slide back and forth (and that loose bolt created a lot of shrapnel).  Speedometer gear was just the tip of the iceberg!  Will need to pull the rear end back to reach into the u-joint and replace that bolt. Any idea of torque setting for same?  I might add some locktite to the new one! See photo for bolt in question - includes at least one spacer washer (which created some of the shrapnel apparently.  One lock washer was intact in the bottom of the housing).  This hobby just keeps on presenting challenges!

To get the torque tube to back off from the u-joint area, jack up the rear of your vehicle, but put jack stands under the chassis, not the rear axle housing. Also, put wheel chocks around the front wheels (for safety).

With the axle housing dangling in the air, the torque tube has pulled away from the u-joint housing thus giving you a little more room to work in that area.

Cheers, Dean 

@w-david-penniman The torque charts I found online listed 35 lbs  for a lubricated bolt and 46 lbs for a dry one and those are for a 3/8 grade bolt. I am guessing that is the size of the bolt-if not just google " bolt torque chart". Be sure to flush the tranny and refill with new oil. You should also replace the bolt and lock washer. Be sure to note how the trunnion bearings are located in the ujoint as one side is beveled. The bevel i believe goes towards the center.

Thanks for all the help on my (speedometer gear??) problem -that has grown from damaged speedometer gear to bolt coming loose holding half the u-joint to transmission output shaft and creating shrapnel as well as damaging the said gear.  Found a bolt that fits in the shaft, but washer seems to be critical. Is it special or can I just grind one to fit?  Have not found a part number for it by itself.  I think the washer is meant to keep the u-joint from sliding back and forth -thus ruining the speedometer output gear - and other things.  Any comments??  Again, thanks for the advice on all this.  Give a mouse a cookie...