833 B to 833OD
I get the impression the o.p. wants to make a B-body OD trans out of parts from an A-body OD trans. So the end product will be a B-body OD.
if so, The o.p. needs the gears from the OD trans and an OD main shaft in B-body length.
The main shafts are different from a 1 to 1 trans and an OD.
The A-body OD main shaft is too short for the B-body trans, however Brewers has them in stock.