Dear Mr. Memo;
A Cheverolet passenger car OD transmission of that era will bolt right in and in some cases won't require the driveshaft lenght being changed.
This will give you exactly what you have now + a 28% reduction (engine speed)in the overdrive mode. These units sell for under $200 plus the cost of a little wiring/relays/switchs etc.
It's a "weekend job" if you have all the parts first.
Good luck, John M......
