I just installed a nice low miles 3.9L from a 95 Disco into my 93 RR LWB. I did a total swap including all accessories which were run by a serpentine belt rather than the older style V-belt acceesories. There were a few minor differences in things like hose locations, but my main concern as I am completeing the hook up is the wiring harness, there is no sensor on the side of the oil pan, or on the oil filter housing.
Where are the oil level/pressure sensors on the disco motor?
The distributor and harness on the 93 has a 2 prong connector, the 95 Disco engine has a 3 prong connector on the distributor. I heard there was an adapter available but rovers north told me it was NLA. Any ideas on how to adapt? Can I swap the entire distibutor from the 4.2 and put it in the 3.9? I have the entire harness from the Disco including ECU, the coil and ign module but dont want to get involved in a harness swap, there must be a simpler way. Any suggestions would be appreciated.

 

No oil level (pan) sensor. Oil pressure on starter side of motor near filter, # 27 or #35 in attached.

 

Amplifier Module Link Lead (Genuine Part # STC1212) - Land Rover ignition from Atlantic British

But it's just the amplifier that is different. you could probably swap the amplifier.

 

there is a guy on ebay that sells one wire hook up distubutors. They are GM HEI distubutors the modual and coil is all contained in the HEI cap. I put one in my jeep years ago, simple one wire hook, just have to find a wire that have a constant 12 when the key is on, and the GM coils come with a tac feed also.

heres the link HEI Land Range Rover V8 Upgrade to GM DISTRIBUTOR NEW!! | eBay

it not cheap but it includes the complete ignition system and replacement parts can be picked up any where.