Sorry to burst your bubble woody, but they weren't the same

. 79-80 had the 4 speed and 20r, 81 has an optional 5 speed, and optional 22r. Stay away from the 81 5 speed. It was built using a 2wd tranny as a model and the bearings are undersized for the increased load. That makes them whine really loud and come apart earlier. I put a 84 tranny in my 81 and never had a problem. (250k on tranny 300k on truck) The five speed got better in 82 and 83. 82 and 83 also supposedly had stronger axles, but that is just hearsay. I'll agrre that the EFI can be an advantage, but after driving a 22r with a weber in my 81 and driving a 22re in my 94 4runner I would take the carbed engine anyday. I don't belive that you can get a mini of those years with cruise control, but I do know that AC came with some SR5 models. One other thing, the 84+ had double skin beds so stuff rattling around in the back didn't screw up the outside, but tree damage was harder to fix, The bed also made it heavier and therefore slower. Some of the trucks had the dual side latch tailgate, which is stronger and more reliable than the center handle gate, but I don't know which years they were availiable. All had the double cardan front shaft(PITA to change u-joints) and manual hubs. IMHO they are great trucks but there isn't much room for a family in there(hence the 80)
I hope this helps and good luck
Dan