I thought I'd make a quick post about my experiences with buying used landrover 3.5 EFI parts for use on an SD1 vitesse (mine is a single plenum):

Airflow meter:

Exactly the same appearance and part numbers as the standard SD1 item. Functions the same.

Engine ECU:

PRC 7440, additional number above barcode: 84941 A. Idle and general running exactly the same as the standard ECU. Rev limiter not yet explored.

Disributor:

I purchased a rangerover classic distributor bearing the same model number (35DLM8) as the SD1 unit. Despite being largely similar, they were not the same (a part number on the castings did differ).

The internal parts are the same, but the main difference is the location of the ignition amplifer and the aluminium casting of the distributor body is different to allow this. The pick-up sensor inside, mounted to the baseplate is also in a difference position, although still in time with the toothed reluctor wheel. The slot in the end of the drive aligns the same with the rotor arm.

The unit can be fitted and will work the same as the standard unit, but when fitting you must use another feature other than the amplifier wiring cutout (as shown in Haynes) to align the rotor arm.

The amplifer will also foul the cylinder head at more than 10 degrees of advance. The metal bracket that secures the coil trigger wiring needed to be removed to allowing timing up (5-6 degrees BTDC), but can be replaced once the disributor is in its final position. The amplifer also obscures the clamp bolt making replacement/tightening awkward, but not impossible.

Why on earth these issues don't afflict the range rover I have no idea...

One solution would be to transfer the working internals into the SD1 casting, which I may do at a later date.

This information may be useful as SD1 listed spares aren't always thick on the ground, and often a landrover equivilent is cheaper to buy.