1966 Fairlane With 502

john48404way said:

We reset the initial to 30* I do not know what the total advance is Its Ignition system is MSD.
Runs about the same. Getting some dieseling or run on when shut down.

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Whoa! Initial (base idle) timing is 30°? That's dangerous, as it will add unknown timing as it revs.

As you do not know the centrifugal advance in your distributor, you can set timing by total (all-in) advance at high-rpm. Disconnect and plug the carb-side of your vacuum advance (if you have it). While watching the timing with the timing light, rev the engine until the timing advance stops adding timing. Note the degrees. Adjust the distributor position until the total timing (all-in) when revving to all-in is 34°.

If it were me, I would confirm exact timing mark location with a $10 spark plug thread timing stop (or make your own). Then if you do not have a dial-back timing light; add measured marks every 5° to 40°, before setting timing as-above. 34° is only a place to begin timing tuning, but should be much closer than guessing, and certainly safer than what it is.

[EDIT] Dynamometers are test devices, and may be calibrated or corrected to read anything you like. Do not regard dyno sheets as proof of anything. They are meant to collect relative measurements for tuning under stable and adjusted conditions, with proper calibrations, corrections and operation.