How hard is it going to be to put the 22RE out of my '91 pickup into my '87 4Runner? Will I just be able to set it in and hook everything up or will I have to change some wiring? I need ya'lls insight on this.

 

the engines have the same long block(oil pan to valve cover) but the intakes and exhaust are going to be slightly different('91 probably won't have an O2 sensor on the exhaust, and the intake has a straight plenum).

the very easiest way to swap the '91 engine is to pull the manifolds/sensors/etc off of it, bolt the engine into your '87, then bolt the manifolds and all from the '87 onto the '91 long block.