I haven't owned many toyotas, buuut this spring will be swapping a 4ac into a friend's 87 T4. The donor car was an AE86 SR5 and the motor had been meticulously maintained by it's previous owner who swapped to a 20v blacktop. After much reading I feel it should be a fairly direct swap aside from swapping the upper and lower oil pans/front diff onto the new motor. There are some very detailed walkthroughs here which have helped a ton, however they have all been completed with 4a's that were originally mounted transversely, so bonus for us, I suppose.
I also plan to grab a T4 to throw a 20v 4a into once I have the time/money. My daily is a 1980 Corolla, 3tc, header, weber 38, TRD springs 8/6k, shortened MR2 strut housings etc etc. It looks like pooh, but meh, it's coming along.

Anyways, happy to be here, hope I'll learn some neat stuff!