So I spoke on the phone for about 20 minutes with a guy that calls himself the specialist of Land Cruisers in Quebec and those are the options he came up with;
Easy option if I'm not bound to the mythic model 60 bodies; the HDJ80. He believes its a very sustainable engine and there are a lot with auto transmission on plus its an overall easier car to find in good conditions.
More money more time option; buy a non-rusted HJ60 automatic or FJ62 and swap both engine and transmission for a HDJ80 engine plus transmission.
I think you mainly trade one set of problems associated with gasolene engines for a different set of problems associated with a diesel engine. Its really a lot more with how you drive the engine and how you maintain it. The internals are the same in both engines though the shapes may be different. A 2F engine in an FJ60 drives very much like a diesel...slow revving, torque made at low rpm, etc. The 2H is a little better on fuel than the 2F. my 2F has 336,000 KM on it and it doesn't burn any oil between oil changes. Also consider that the 60's, 61's, 62's available are all pushing 30 to 40 years old at this point and reliability is a relative term. I think if you don't restrict yourself to diesel your options will be increased tremendously as well as your ability to find a clean truck in your price range.
3B or 2H are both engines which will last a lifetime with good care and love but bit sluggish without after market turbos. A BJ60 though comes standard only on 4 speed gearbox..whereas a HJ60 comes with 5 speed gearbox..A 12ht engine is also a superb reliable engine with good performance and good with auto on h55 gearbox. A BJ60 look cool with round headlamps though..A HJ60 with square headlamps looks more mean. A BJ60 with 12HT on H55 Auto will be ideal for You