Anthony, it is totally possible but not exactly easy or cheap by most people's standards. I actually am wrapping up installing a late-model 3.4L into an '89 4Runner. But in my case, the donor truck was already a 3.0L so that makes the swap much easier since the tranny and motor mounts bolt right up. Check out my website (link in my signature to '89 4Runner) for more info and also go to some other more technical forums such as:
Yota Tech
and once there, use the search feature and type in "22re 3.4L swap" or any other combination of terms such as "engine swap v6" etc....
The manufacturer to talk to about this is
Off-Road Solutions
they make wiring harness kits to complete the job.