If I were to do a diesel conversion I'd use the 4JB1-T 2.8L engine. Its more reliable and has less issues than any of the subsequent engines (3.1 and 3.0L). Note you'd have to go with the transmission swap for this as well. and you'd very likely lose TOD.

It was available in Troopers (Bighorns) and Rodeos outside of north america.

T.