Motor Swap

I assume it is the original trans. I know that trans is good. The other is a crap shoot. If I could swap components or purchase an adapter it would be the better option. If that can't be done I can swap in the trans that is currently bolted on to a 71 slant.

I at some point I want to do the HEI upgrade. I assume the distributor in the 81 would work for that application? Since I don't have the parts collected yet I was planning to swap distributors temporarily.