OD auto for a small block??

The A500 and A518 started in the mid late 80's. The designation was changed to 42RH and 46RH in the early 90's (same tranny with some internal improvements) in the mid/late 90's the tranny added more electronic controls and became the 42RE and 46RE. There is also a 44RE which is a 42RE with more clutches to give it more capacity and is found behind v6 4x4 Dakota's and Durangos (maybe some jeeps too).

All the A500's had lock up torque converters but the early A518's didn't. You don't want a 42RE or 46RE because there is not a controller available to make these work on a retrofit into an older car.

NOTE: either an A500/42RH or A518/46RH will require that you cut the torsion bar cross member and the floor to expand that area for clearance with the OD section of the tranny.