LPG is in general, not so sure in 4x4 but quite a few Nissan's run it.
Me being a engine reconditioner up until the mid 90's and back then every man and his dog was converting.
Personally I hate the stuff, The damage I saw due to it being such a dry fuel was extensive and lots of fly by nighters making & selling oil injection to compensate for the problem made good money.
I could go into a lot more detail of the requirement's for LPG but serf-ice to say the requirement's that LPG & Petrol engines are very different Compression ratio / ignition timings / advance curves / valve guides & seals / Valves & valve seat all com into play.
While due fuel set up's are around but non are 100% on both, Far better to have 1 only fuel and the engine designed for the selected fuel.