Having owned an 89 and my 84 twice, here's my opinion. If you don't need a SFA, get a late model SR5 with the 22re. You will get more creature comforts and a wider rear axle which people with 84/85 models like to swap in. If you decide that you really want SFA, you can do a SFA swap. Very common, and many kits. The problem that I see with 84 and especially the 85 rigs is that everyone considers them to be the holy grails of Toyota 4runners/trucks and that drives up the price. The IFS models get looked over, and many may not have been beat on as much as the SFA.
If you are dead set on a SFA, then that would mean that you plan to do some really difficult wheeling? The 85 having EFI would be best so that you don't stall out. However, my 84 with a Weber has been vertical nose up and nose down and has only stalled once, and I was able to get it started again and climb up the hill. The 85 EFI
s have a more common block/head that you can buy rebuilt and hi performance heads for cheap. The 84 is the older style block and you will have to buy parts and have a head builder or yourself put them in.
Final options, and I say this with a grain of salt. You can take your chances with an 88/89 SR5 with the 3.0. You can pick them up cheap, and you should. They have a bad reputation, but you might get lucky. On the up side, if you get a good one, it will have about 150 HP, if it blows, your only reasonable option is swapping in a 3.4. Then you will be the envy of all the folks with a 22re.