steveww wrote:

Modern ECU do more than just control the spark and fuel. That's what makes them tricky to swap over as part of an engine swap. However, there are numerous stand alone ECUs from various manufactures available. I've used Motec in the past. Getting the ECU connected up is easy, the tricky part is developing the map. This takes many hours on a rolling road which soon gets expensive.

If I had the time and the money, I'd like to try the JLR 4.4 diesel V8 in a Defender.