Why does everyone assume the 40 is so much heavier than a Taco and that an engine with more rated torque and HP will not move it effectively.
Stock curb weight of a 40 is something like 3500 pounds or less. Stock curb weight of a Taco, at least 3500 pounds or more. I have a 96 T100 extra cab, it is right around 4000 pounds (real world number). Stock curb weight of the last years of 4runners that had the 3.4, well over 4000 pounds.
I can confirm 1F powered 40 and 2F FJ60 cannot outperform my T100 on the highway. They both run out of power in the top end. Direct comparison, identical grade (local straight hill, 5%, 1mile long), 4th gear in each, the T100 will continue to accelerate and hold 65 or more for entire hill, 60 will try to hold 60 for awhile but falls off to 55 by the top. Best runs with the 1F, 45-50 at the top. The F engines just get wheezy, later model 2F is better than all earlier ones.
Drop the T100 into 3rd and look out, but you are running 4500+ RPM, but she will hold some power there. However, that is the true weak point of the 3.4, it makes all of its best power high in the RPM range, and does okay on light cruise in the lower revs. The F engines will out grunt the 3.4 all day in the low revs driving around in the woods or in town. They just bring on the torque so much earlier. But I know I would not feel comfortable pulling our 4000+ pound camper with an F engine. Pulled 2000+ pounds many times with them, but hills got pretty dicey, power is just not there and you have the F's really overrevedd in 3rd trying to hold any kind of decent speed.
My greatest complaint of the 3.4 is low end torque issue, I have to be very careful with the clutch even with an empty truck. Put a big load behind it and you have to feather the crap out of it to get going on any grade. I use low range alot for that type of work. That is where I miss an F, can pretty much just dump the clutch anytime she will recover and go. But, my T100 is still purring along at 274,000 miles, original clutch even, they are good running engines.
I think it would be a decent swap, but hard due to lack of support. I think an auto from an FJ62 would be a very easy, almost bolt in solution for a disabled individual. Would want to run an FJ60 2F in front of it atleast, it will rob power. On the other hand, Marlin had mentioned working on some adpaters for cruiser transfer cases to minitruck gear, probably didn't have that variant of 3.4 mated auto in mind though.
