For what it is worth, I have a few decades of experience of hunting and 4x4s. My experience of the SJ410 first started back in the late 1980's, and continues to this day. Though I dont one, a few of my friends do.
Now if I may venture my opinion, if offroad performance is what one is looking for then the swaps worth considering are the Toyota 2C, 2C-T (both 2000cc, the first being being naturally aspirated and the second one turbocharged) and 3C-T (2200cc turbocharged) in diesel, and then the Samurai 1.3 ltr, Vitara 1.6 ltr, Toyota 3Y (2000cc), 4Y (2200cc) and 3S-GE(2000cc).
Of all the above mentioned swaps, the most powerful ones are the 3C-T, the 4Y and 3S-GE. All these engines produced power reliably and they have enough low end and mid range torque for the SJ410's original axle gearing. The Samurai 1.3 ltr engine is also a good one, but its not in the same league as the above 3 engines.
If you opt for any one of the Toyota engines, I would strongly advise you to use a Toyota Hilux/Surf manual transmission. Its a better and stronger unit than the Suzuki's own strangely coupled speed gear and transfer case. All my friends who have swapped engines (mostly Toyota engines) in their SJ410's have also switched to the Hilux/Surf manual gearbox (with the 4 wheel drive transfer case).