From the posts above, it sounds like you have the 24V engine. However, IF it is a 12V, it will probably work. I recently put an engine from a '91 (Gen I) into a '92 (Gen II), complete from oil pan to valve covers. I have to swap the intake manifolds so that the upper & lower Gen II manifold stayed in the Gen II truck. I've been driving it now for several months.

90 LWB Montero, 270k, 265/75R16, 16x8 ARE Bajas, Budget Lift, Towbar, Aux Brakes (towed with camper), Jotto Desk, remote oil filter
92 bone stock base model beater
Parting out 4 more