I have a cracked block on my 2003 Disco 2 with a 4.6. I purchased a 4.0 to replace it and am wondering... can I put the 4.6 crank in the 4.0 block without changing anything else. I am not rebuilding the 4.0 as it has few miles on it and has no issues, but as I have already got the 4.6 crank and new bearings, would it be OK to swap that out and increase the 4.0 to 4.6 or is there a difference in the connecting rods too?

 

According the the 4.0L & 4.6L overhaul manual, the connecting rods for the 4.6 are approximately 5mm shorter.

 

Crank and rods for the displacement jump