For starters you will need an adaptor/bellhouse shell to mate the 8ba to the transmission. You will need the starter plate that goes with it as well. There is a document that shows the different combinations, but for some reason I can't get it to upload.
I'm not a very good source on 8ba engines, but believe you could covert it over to use most of your current 59a parts. Such as water pumps, front timing cover, distributor, even the heads and intake manifold. There are some minor modifications required but none of them are a big deal.