Watch out for the wiring harness, I would doubt a carb'd truck would have the correct loom to run the ECU for the Fuel injection (no matter how archaic that "computer is...)
That's my only thought. Otherwise I'd imagine it'd just be mater of swapin the head and manifold.
Edit: o wait, you have a 22RE and you're looking into using the 22R block... In THAT case I think you should be OK.
*EMS/Fire/Rescue/Winderness EMS guy... it comes in handy from time to time.*
- 95 Toyota 4Runner SR5 Limited: Project "4Rescue2" underway
*1KZ-TE Diesel, SAS, OME Rear Leaf suspension conversion, Custom Armor... I'm going grey faster then this truck is getting finished.
- 89 Toyota 4Runner dubbed "Project 4Rescue": Rafting/Exploration rig, Rescue rig, daily driver, Home away from home...
*22RE 5spd. OME suspension, 33x10.50 BFG At's, Marlin Armor, 389K miles