someone in 4x4ph asked this already. and my advice was to not change the engine...sayang. proper maintenance, maybe an overhaul, and the engine will give you better service than say, a recon diesel that has led a hard life someplace else.

why change sa diesel? maninibago ka lang sa performance. tsaka tama si sir otep...chop job na ganun ka extensive and you can expect reliability issues later on. i've owned a pajero 2.5td and once the engine troubles start showing up, you'll never see the end of it. this is the risk you'll take if you get a 2nd hand engine. not to mention changing the gearbox (hindi yata swak, per my mechanic friend, because i've considered this once before, diesel to gas nga lang, badtrip kasi yung td engine ko nun, maya't maya may nangyayari.)

2.6 astron ba yan? get the carb cleaned, get good quality filters and plugs, change to a better oil...aayos uli yan, if you don't want an overhaul for the time being.