Hi all im new here not sure im in the correct place to post this,but I have a 1999 4.0 v8 and I found a rebuilt 3.9 v8 1994 what will I need to do to make it work any help with this I would owe you a beer.

 

Engine management would be different (sensors, etc.). Here is short booklet that compares the various years and parts. ECU certainly different. You'ld have to compare everything, like injectors, knock sensors, MAF, etc.

 

Depends on if you have a DI or a DII and in which country you live.
Both the DI and DII were sold in the US in '99.

 

Assuming US stuff, there is no easy way to put a 95 or older engine in a 96 and newer disco. You can, however, put newer engines in the older distributor cars without TOO much crazy hassle, especially if they are both serpentine belt engines. Just need a front cover, cam, intake, and dizzy.

Gets a little more funky with trying to put a serpentine engine where a v-belt engine was.