That would be so sweet if it was possible. I have a 2000 3.4 4x4 5 speed and I believe the HP of the 4.0 is almost the same as the original V-8 but here is where I have questions, I know the 4.0 comes with the option of a 6 speed manual and I would actually be more interested in seeing if I could swap out my 5 speed manual 4x4 for the 6 speed manual, it would be so cool!
This sounds like a good swap. I may be mistaken but I think the 4.0 v6 has more hp that the 4.7 V8 for that year. If it is the v6 from the 2nd gen tacoma, it has more hp but less torque than the 4.7, but the VVT-I 4.7 has more hp and torque than both. The 4.0V6 is a good motor, I used to drive a 2nd gen tacoma all the time, and it is no slouch. When my truck was stock, I wont say I raced one(against forum policy) but I did manage to beat one, and not by much.
As far as if it will bolt in or not, sorry but I don't know.
im sure the motor mounts are diff. ive seen both motors pulled out at my boys dismantling yard.. that alone is a lot of work to do the custom motor mounts.. then u gotta think about the harness and wiring issues. for the $$ might not be worth it. i had a 3.4 sc at 18lbs w/ meth.. automatic.. and kept up w/ too many v8s