No, not really - just pull your engine.... before you install the Diamante block, grind off the 2 dowel pins on the Diamante engine that interfere with the A/C bracket.

You'll also need to swap your oil pan, water pump, oil pump, oil pickup tube, alternator bracket, driver side rear cam sprocket cover, distributor, upper & lower intake, rear engine hanger, dipstick, oil filter adapter - don't remember everything.... just put the Diamante engine on a stand, keep the Montero engine close by and grab what you need as you go along.

Frank

'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum