I have not used a 123 vacuum distributor. For a non vacuum type: choose your advance curve, choose your static timing, make a static timing mark on the pulley, set engine to static timing mark, rotate distributor counter clock wise until green LED just turns on.
Calculating the timing mark is described in an earlier post in this thread.
This probably works for vacuum advance distributors too.
85 GTV6 3L
76 Suzuki GT500
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