Civic wagons! Auto to manual and back again!

Greetings all! I've owned quite a few wagons over the years, manuals and automatics, 4wd and fwd. I'm currently buying a 1991 white fwd/auto back from a friend; i sold it to her 5 yrs ago with 64k mi. It now has 74k mi. I currently have a 1991 5 speed wagon. I'm considering literally swapping the transmissions. Lots of info on auto to 5 speed out there, none on the other way around. I have a lift in my shop, so no worries there, and more than enough air tools to get myself into trouble. My other car (i've also owned a few) is my 1st gen acura legend coupe/5 speed (vin #00003, but that is a different story) and a 1983 dodge d15/slant six i converted from auto to 3 speed/od miser last winter. But back to the civic; i just can't resist the white civic and its ability to resist solar gain in the summer. This car is near mint, with no (zero) rust, but i sold it because i couldn't stand the auto. Swap the trannies or drop the sub chassis? Any/all comments welcome! Thanks!