Reply to "ignition timing curve"

Bill,

run the black "stop bushing" in the distributor, which limits centifugal advance to only 18 degrees.

Run one heavy silver spring & one light silver spring, which will result in the 18 degrees coming in at 3000 rpm.

Optimize the static (initial) advance setting with the following method: With the engine up to temp and idling, vacuum advance connected normally, slowly turn the distributor in the advance direction (clockwise?). As you turn the distributor, the idle speed should increase, continue to turn the distributor until you just reach the point where the idle speed stops increasing, this is the ideal setting for the distributor at idle. The intake manifold vacuum will be at it's highest point, the exhaust temps will be at their lowest temps, you'll have more low end torque, better drivability, less heat load on the cooling system, and a better idle.

You'll then need to optimize the setting of the idle jets, and re adjust the idle speed with the throttle stop screw.

Your advanced friend on the DTBB, George