After 22 years, the cars started and ran.
Well, started up and ran after I cleaned out the fuel lines that were clogged with tar and the carb floats were stuck.
Fuel pump gave out a minute into the run but I have the donor car fuel pump and hooked it up with great success.
Smoked for a bit, then ran great after about 2 minutes. Engine sounds great and smooth despite the carb being jammed with crud.
Swapped out the "new" engines' black valve cover with the period-correct cast CVCC valve cover just to make it look better.