When distributors look the same but have different numbers, the difference is usually in both the mechanical and vacuum advance curves which could also affect the base/initial timing setting.

What you are trying to do by seeking out the difference is smart and can be critical. A solution to this may be finding the advance curve to your current distributor and then having the replacement one curved to the specs of the old one. This would take into account the factory tuning, compression ratio, valve timing and gear ratios your car.

The curves are best checked and modified in a distributor testing machine and...after all this being said...i'm sorry but I do not know where to point you toward the curve specs, so please let us know if you find them.

Good luck!!!

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