The 2F is a long stoke engine that hits its torque peak around 1,800 RPM. My understanding is the 3F is closer to "square" and revs higher for more horsepower power. It hits its torque peak at 3,000 RPM. Along with its higer revs, the 3f is fuel injected. The 3F should be a better highway cruising engine. For offroading and grunting up steep mountain grades, that 2F works real good. With the 2F I find myself not downshifting out of turns on mountain trails; the 2F seems to have an endless capacity for lugging up grades at 1,800 RPM. This being said, my pushrods are probably all bent like Italian breadsticks!!!
To me, I think the 3FE is really a fuel injected 2F, with many of the same characteristics. SO the real decision is, do you want to stay with a carb, or go with fuel injection. The fuel injection does get you a bit more power, and a complex wiring problem to solve.
I have a 3FE sitting in the garage waiting for a truck to put it in.
Surprisingly until you examine it, the 2F actually lives better at higher RPM than the 3F. Short rods and short bore combine to create fatal side loading on the piston skirts at RPMs where the 2F rod bolts are still surviving.
The 2FE is the motor that Toyota really should have made.
there's a small difference between 2f and 3f(e) - about 200cmc and if you don't live on the southern hemisphere, stay on 2F - you'll find parts for it.
for my FJ62V 3F carb I'm looking for quite a while for some gaskets...