for 38s your gonna want 5.29s. usually its 4.88s for 33s and up, and 5.29s for 35s and up
the 22RE is much better when you flop it on its side, it will start much faster than a carbed 22R, and like cheesemaker said, there are many down sides to a carbed 22R. i dont know why you heard carbed was better?
if its for only offroad and your budget supports it, id go with a 22R and do a propane conversion. but the best year for sure is an 85 because thats got the SFA and EFI. again, depends on your budget, how much you want to build it etc... like simp said for 38s you will need crossover steering.