Salaams, hardly an expert but have messed around a bit now.
Here is my advice. Do not go for an engine that was not an original option with the body from the factory (I speak from experience :)) . Eg. The Gen 1 was most popular in the various 4d56 versions and the 3.0 v6. I believe there was another petrol version as well but was not as well regarded.
Next best advice - only consider an engine and gear swap from a half cut body. Especially where it comes down to the petrol variants. You can go another route where it involves simple diesel engines if the first option is not available/feasible.
You can do some pretty spectacular things with the stock 4d56. We can discuss over the phone. If you want to go for the v6, its common myth to go for the version with the distributor and not one with the coils as they can be hard to replace/expensive/tough to find.
You should not consider the 4m40 for your gen 1 for reasons already mentioned and way too much effort involved for a questionable outcome.
I am guilty of putting in a 2jz vvti in a gen 1. Supremely fast, the fastest gen 1, 3 door, I was aware of, but one of the least reliable at that time.
Best advice - stay stock. Tune your current 4d56 variant. Enjoy it offroad. There is something about an old school diesel off the road that is just so pure and the "done" thing.
Happy wheeling.
PS. Don't visit the forums as much as I would have liked to anymore. 03018400909. Please sms if you would like to discuss.
Rao.
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