it has been done. there was a thread in YT about it. some guy in Texas did the importing and swapping
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Diesel toys in Texas is the company, he is importing the bigger 4.0 liter diesel and dropping them into FJ cruisers and newer Tacomas and some 4RUNNERS
that's the one. but there's no toyota 4.0L TD engine for 4WDs/SUVs. only the 3.0L I4, 4.2L I6, and 4.5L V8.
What he's putting on the FJCs, Tacomas, & 4Runners is the 3.0L 1KZ-TE or 1KD-FTV.
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Nice truck, I haven't seen another 3rd Gen Surf in WPG yet, I miss mine all the time. If you have any questions let me know.
FYI: you can wire the DRL's to the turn signal lights below the headlights, perfectly legal. You'll need the amber corner lenses from a 4runner as well to pass safety. You'll likely get called for the seatbelts when you take it in for safety, you need to swap to the 4runner ones with the proper tags on them.