From the "Drivetrain Swap Question" Thread:
The 2.7l 3RZ Engine swap is much much much easier than many fear.
In fact, your friend can use his existing stock W56 and transfercase, as it is a direct bolt on to the 3RZ's W59 bellhousing.
As for wiring, about 75% of the wires are self contained in the Engine > ECU harness, so all that is left to wire in would be the idiot gauges, ignition, alternator, starter, battery, and possibly rewire your headlights and blinkers.
As for the exhaust, I just routed mine down and below my bellhousing and placed my OBD-II cat right in the stock location as my factory cat, so everything up to the cat is compatible so he doesn't even have to change his exhaust system if he doesnt want to.
The factory 2-core radiator should be sufficient, but I would recommend using a 3-core rad. from either a 86-87' Turbo 22R-TE p/u or from a 3.0 3VZ 88-95 p/u.
If you have never done an engine swap that requires wiring before, then expect to take about a month to get it finished.
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New engine mounts must be created. I cut my stock mounts off my frame and made new ones, and with a 1985 Swap that I am working on, we just modified the Tacoma engine mounts to fit right in the stock frame mounts, so no cutting on the frame was required.
Crossmember: For all 84+ rigs, stock crossmember works in the stock location. For 79-83 trucks, the crossmember will need to be moved reward as the newer style transmissions (g- or W-series) are a bit longer (~4") than the old school trans (L-series).
