I bought my 92 brand new, and IIRC, there was a recall on the 4WD trucks (built around that time) because the clutch or pressure plate was too weak, and allowing too much slippage. I was told that the clutches were the same as the 2wds, but that the 2wd did not show the same problem, so they were not recalled (I don't know any of the details - someone correct me or clarify please). Use the 4WD flywheel, for sure. I personally would recommend, while it is apart, put new clutch kit in (pressure plate,clutch disk, throwout braring, and break the glaze on the flywheel). Would be hell to have to pull it all back apart again in 6 months because a clutch part failed.
When I swapped the 2WD engine into my 4WD, the only difference I found with the installation of the long block was the little wing braces that attach from the bottom side of the block to the bottom of the bellhousing. They are not interchangeable between the 2 and 4 WD transmissions. Unbolt them from the block you are pulling out and put them back on the replacement.
