Is this engine any good? Was it a problem child? I just fired one up and it purred so nicely.... And It is smaller than the GM 4.3 v6 (however longer), so it will be easier to fit in my pickup.

The engine is good, but the injection system was not the best.

Not much power, but robust.

How was the EFI not the best, does it have reliability issues? Or was it just poor execution. Possible fixes?

Does the 215/3.5 use the standard BOP bellhousing pattern? Can you mount up a th 350 400 or 700? What auto transmission comes stock behind this engine in the range rover 1986?

Would this engine get better milage than the gm 4.3 v6?

Others will better be able to address the issues of the early efi system.

The block has a unique Rover bellhousing pattern - not the same as Buick. Nothing but Rover stuff will bolt up without adapters. AFAIK, the autobox behind the 3.5 in 1986 was still the TF727 via an adapter ring made by Rover (still available on ebay etc.) and a tailshaft assembly (still available from Ashcroft in the UK as I recall) that mated it to an LT230 transfer box (one of Land Rover's better engineering efforts - the LT230, not the tailshaft assembly). It was way too much gearbox for the engine.

In good order, the 3.5 efi will likely put out @ 170hp and you will see about 12mpg off highway. In summary, you can probably build a more powerful and economical 4.3 bang for buck, but the Rover 3.5 is light.

The early EFI engines used a moving vane airflow sensor. They were easily mucked up and not that reliable. The hotwire system (lucas 13CU, 14CU, 14CUx) is more reliable and less prone to problems.

I think 1986 was the first year for the ZF four speed transmission. The NAS 3.5L EFI was good for only 150 hp in the US when it arrived in 1987. ROW 3.5 EFI's put out 165 hp if memory serves me.

1983-85 was the TF727