while the 4.3 and sb chevy motors everywhere and cheap. it's all the adapters and mods that are big $$$ . i've got a 3.0 in my 4runner and yes it lacks low end torque and is a pain in the butt to work on. plus it just keeps on running and i get about 18 mpg. i think the easy best off road mod would be the mc tranny with a low first gear. i think a 89 4 runner would be cool with a toyota 3.4.  190 hp would get it  . plus the mounts and tranny would match up.