A lot of the T100 and Tundra's with the 3.4L are 2wd.
Anyway here is the link to the place where I heard of a guy using a buick 3.8L
http://www.off-road.com/toyota/buick_v6_swap.html

I also heard of a guy using a Ford Mustang V8 but I don't remember where but he went through alot to get it working right.