I don't know that answer, but my fuel pump from my 89 fit into that tank, I just have to fix the sending unit to the guage to be shorter and actually read the gas level.
I am. But the backs of the tank are shaped differently. Once I get it figured out I'll measure it and post up how long it needs to be to work properly.
I forgot to mention. The alternator on an 84 mounts differently then one from an 89. And the plugs for the 89 alternator won't work on an 84 alternator. I swapped the brackets over. But it means undoing two bolts holing the motor mount to the engine with on bolt that's a pain in the rear to get on and off. I don't know if you want to do that or not but this way you know the difference between those two alternators
'84 was the last of the alternators without an internal regulator. The voltage regulator sits on the inner fender on the driver's side, near the coil. Everything is different: mount, plugs, even the rated output. Go with the newer one if you can.
Like I said I would I finally fixed the gas guage issue. I bent the sender unit from the 89 ~1.75". You can also pull the one from your old tank to measure it for an exact fit
Started the teardown of my RE. I'm debating on replacing the head. Question. How do I tell if this is an original Japanese head? It's got some issues, someone messed up a spark plug thread and put a heli coil down in the cylinder. It got blown away and destroyed the valve.