22R engines had a harness from the factory, mostly smog junk and about 4 wires(i'm pretty sure) for the factory carb for the choke and idle solenoid etc. the 22RE has a harness, since it's multi port fuel injected. not the hardest thing to rig up, but definitely a project
if you put a weber on a 22R, the only wires you'll need are spark, coil ignitor and distributor.
not to mention, 20R and 22R motors are dirt cheap. the 20R was made from '75-80 and the 22R was made from '81-95, very easy to find.
for tranny choices, the best are W or R series trannies. L or G series will get the job done, but aren't nearly as strong. for a 2wd, you'll want to look for a W50 or W55, they came in fuel injected trucks and celicas. as for a 4wd pickup the best one to look for is a R151F or W56. all transmissions from trucks made before 1996, celicas before 1986, and coronas before 1981(i think) will interchange. they don't care if they're behind a 20R or 22R or 22RE or 22RTE(rare turbo from '86-87), either. however, transmissions made before 1984 are usually 4.5" shorter...don't think it's an issue because you'll probably end up getting your driveline reworked anyway
if you put an aftermarket cam, header and weber carb on these little guys, and maybe do a little head work, they'll throw you back in your seat quite nicely. they had around 140lbs of torque stock, only 96hp but it can be easily raised.
and lastly, to put how reliable they are, i have a 20R engine in my truck and it's seen 311,000 miles without a single rebuild
