It's entirely possible that the thyristor (or whatever's on the boards) is the same, or similar enough, so that the connectors can be swapped and the ECU would notice the difference. Again, I'm not saying it can't be done, just that it's not "unplug this engine and plug that one in".
I do know...
Just to be clear, the crank position sensor in the newer engines wouldn't pose a problem for installation in to the older model 80, as long as the original distributor was used (item 4):
Same for the two piece oil pan in the newer engine: you'd use the earlier engine's oil pan, so it doesn't...
The early engines used VAF instead of the MAF the later engines used, so that won't be a plug and play installation. You lose the PAIR system if you install the later engine in the early models, so that has to be accounted for. All this can be done, but it's not plug and play. It may be...