In 17-Instruments when you do Output Tests, for the revs does it start at 0 go to 6000 then settle at 3000?
Have the needles been removed before? If it seems the needle is out of phase, so you can move it almost full circle by hand (anti-clockwise) to where it should be.
However from what you suggest the 'out' figure is not linear, so are there any other signs that the clocks may have come from a petrol, with a diesel insert being used?
Have you got a full part number?