Hope I'm in the right forum....

Any chance of rebuilding a 4.0 block with a 4.6 crank and connecting rods? I understand the engine ecu will need to be swapped to a 4.6 version.

 

The ecu does not need to be swapped. The becm needs to be reconfigured for a 4.6 engine. Which is a simple as checking a box on a computer. Granted you have that computer... The swap should work. BTW, what year of rover do you have? It makes a difference. From what I've found, the bosch blocks are not the same as gems.

 

1999 Bosch RR but I may have a GEMS 4.0 from a 1996 Disco as the rebuild candidate.

 

I have a friend that is a Rover Mechanic and he swapped the crank to one from a 4.6 in his 4.0 and he says it feels more powerful.