Easiest and cheapest swap would be to put in an A833 OD four speed. With the right parts, this would be a bolt in. If your still running a stick in the car the only 2 changes would be the tranny itself and possibly the bellhousing.

Tranny: The A883 OD had several small variations. Basically what you would need would be the version with the long tail shaft which would physically match the original 4 speed that had been in the car. This is easy to identify due 2 shifter mounting pads located on the tail housing.

All OD 833s had a 5 1/8" pilot bearing reatiner. If you have a bellhousing with the medium size pilot bearing hole (4.80"), you can have the 5.125 bearing retainer turned down to fit.

The giveaways to tell is you have an A833 OD are:

The big bearing reatainer,

They usually have an aluminum case instead of cast iron (although some standard A833 were in aluminum cases and some OD 833s were in cast irom cases)

The shift arms on the cover will have one pointed up and the other down.

THE ONLY REAL WAY TO CHECK IF ITS AN A833 OD IS TO PULL THE COVER AND COUNT TEETH.