I grew up with early model landcruisers like the FJ40's and I will tell you it is much easier to drop a small block Chevy in, many are doing it in the states and I mean many. Mostly 5.7Liter 350ci Chevy V8's and their are alot of adaptors out their as well for the swap...
My older brother currently owns a 74 Toyota Landcruiser stock and restored to 100% and I am pushing him to try and drop a Chevy or a IUZ-FE engine in it. We cannot find out info on that IUZ..swap either... I personally droped a 283, 327 and a 350ci motors in my 1974 beast of a landcruiser many years ago... The 283CI Chevy was my best engine with an RV cam and headers.. The corvette 327ci was the worst, no lowend torque..
I was thinking of droping my SC400 Iuz-fe motor into my current 1993 Toyota LandCruiser but found it to be too much trouble for maybe just a little more performance then the current stock motor so I said let me supercharge it instead...Let me know your finding on the FJ40 - Iuz-fe swap I would love to know...