Is there any major differences between a 1990 FE 22re and a 1992 FE 22re that would create any problem changing out the engines to the 90 model truck?
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Had some issues but got all worked out.
I had to use the wire harness from the 90 because the 92 was auto with 2 WD and had a different computer and more connections inside the cab. I had to change 2 parts on the fuel injection from the 90 to the 92 engine because of the wireing harness difference. 3.Had to use the coil from the 92 so it would plug into the distributor. 4.Had to change the oil pan so it did not hit front weel drive and along with that I had to change oil pick up tube. Last I had to get a pilot shaft bearing because the 92 did not have one. Engine runs great

 

should be fine....

 

don't think there is any difference

 

There was a change in the clutch setup in '92. I don't think this results in any change in the block itself. You probably just have to make sure and use the flywheel/clutch assembly off of the '90 and put it on the '92 engine. The clutch changed in 08/1992.
From a quick bit of net research, the pilot bearing and release bearing are the same in that period.
I haven't found any info on the flywheel yet, but I'm looking as I type this...can't find anything offhand. I guess, just make sure and use the flywheel off the 90 on the '92 or measure them and if there is no difference, use the one in the best shape.
Good luck!