Interesting discussion. Though I think no group consensus as to what is correct or original was achieved. I know that both of my 50 3600 pickups with SM-420 trans and front torque-tube (enclosed) driveshaft had NO rear trans mount/ crossmember. There is no provision, no lugs, no ears on the SM-420 case for a mount.
I thought, maybe mistakenly, that only 3100's with 3-speed had the trans mount.
I'm only saying...
