diff: 3.27 or 3.89???

[irish44j]

I recently pulled the diff out of the junked part-car GT6+ I have. Unfortunately, the rest of the drivetrain is gone, so I'm not sure if it's an overdrive or non-OD car. Here in the US, the non-OD GT6s had the 3.27 and the OD cars had a 3.89 I think.

The only markings I can find on the case is "K289" cast into the metal. Any ideas if this means anything, or if there is another way to tell?

[CharlieB]

Turn the two output flanges together one complete revolution & count how many times the input flange turns. 3 1/4 turns = 3.27 diff, just under 4 turns = 3.89 diff.

[Deleted User]

pinion nut colour on 3.27 is red or yellow
3.89 is pale blue