Chris I've noticed with mine, that with the 5.29's I can be in fourth gear at 55mph and still get that fifteen or more up those hills. I guess what Im trying to say is that, you had that motor working hard, where as the 5VZ would have to. So try slowing down a bit you freekin speed freak. 
OK, lets put this in my statement from yesterday....
In my 1981 with a 22r with 250K on it wtih 5.29s and 37s I was able to pull 60-65 the entire way on that same hill and get 16mpg....Thats at full throttle
In my 1986 4runner with a 22re with 4.10s and 37s I was able to pull about 60-65 the entire way and get 15-18mpg... And thats at about 3/4 throttle
