I have a 4.6 L 2003 Disco running on 5 cylinders and want to swap it with a 4.0 L from a 2001 Disco; can I exchange the 2? If so, what are some common woes?

 

I prefer the 4.0L to the 4.6L myself. The power of the 4.6L is nice, but it comes at a cost IMHO, and I'd rather have a stronger 4.0L block from 99-02 vs the 4.6L's from 03-04 that were not the highest quality.

If you could find an 00-02 P38 RR 4.6L you'd probably have better results as they were made earlier with more quality control. LR was already working on the LR3 so the 03-04 D2 was the end of the Buick 215 based V8 and sadly LR wasn't working on improving it any in 03-04, but to get the last ones built and rolled out the door.

As long as you match up 4.0L SAI to 4.6L SAI or 4.0L non SAI to 4.6L non SAI it'll be an exact engine swap. If you get one or the other you'll have to retain your heads to whatever config you need/have.