60 series 2H engine swap

G'day all,
Just wanted to know if any could help with a few Q's regarding 1984 60 series 2H engine swap. I have recently hydraulic locked the engine after dunking it in water. I was always after something with a bit more get up and go than the sluggish 2H. What I am currently looking for is either a reconditiond 2H (which would be a straight swap, with turbo fitted later on) a 12-HD??? or a 1HZ??? What would be the best option here?? I'm not sure if the 12-hd slots straight up to the original five speed, and or if that and the 1HZ requires a full engine and g/box mods???
Have looked up the 6.2 chev diesels but am now a bit weary as the price is a bit steep and not all that crash hot on the remarks found in the recent forums on them.

Could anyone give me some numbers of reputable engine reco's in NSW with warranties.
Cheers, Brighty.