intro and engine swap

[saint60]

hello everybody. my name is nate, i live in st anthony idaho, and recently purchased an 88 corolla alltrac wagon. i drove it for a few months and it did great, although the trans ground almost on every gear (the PO says he swapped in a rebuilt trans, i don't really believe him). anyway, driving home from work about a month ago, the engine goes pop...assuming it threw a rod. there is no oil left in it, but haven't pulled the engine yet to examine to see if there is any holes in the pan or block. anyway, i'm gonna swap a new engine in and have been checking into some stuff. it seems it is a 4afe, though i guess ill need to check the vin. my questions are

1-where do i need to check the vin to ascertain what engine it is?
2-if i choose another a engine, will the computer stuff match up or will i need to get that stuff too? if so, i may as well just try to match up the right engine.
3-when i have the drive train out, what can i do to get the trans working right, shifting smoothly?
4-i have no clue about the difflock on this thing...is the alltrac fulltime awd, with difflock locking up the axles like on my land cruiser? or is it taking it from 2 to 4 wd?

[Rookie_One]

its a full time 4WD FYI, and the only engine that is bolt-on is the 4A-FE 1st gen (1987-1992), you need to modify the engine block to fit it on the tranny if you want to use another 4A engine (yes, you need to check the engine code, not the VIN)

[saint60]

where on the block is the block number? i'm just going to swap in another 4afe. is a 4afe a 4afe is a 4afe no matter what the donor vehicle is?