Years ago I pimped out my CUCV Blazer with a silverado gauge cluster. All I did was de-pin and re-pin the plug end and follow the path on the circuit board finding the proper gauge.
You might try removing the glow plugs (10mm deep socket) and try to turn it over first.
Don't be surprised If the plugs put up a fight coming out.
That will determine step two.
Trying to tune up a JDM mini truck with a carb and points distributor.
My analog dwell meter is for 6 or 8 cylinders. Would I half the 8 cyl. reading for a 4 banger ? Would that be the same for a 3?