Hi Pee,
Assuming you want to do this without a distributor machine, just on the car, here is a start (assuming you have just a simple timing light without a degree knob.) First of all you need to clean your harmonic balancer and paint it white where the scale is. Then you need to extend the degree scale by copying the 0 to 10Deg scale on the Harm bal onto a stiff paper card. Set the zero mark of the card on the ten Deg mark on the balancer and with a Sharpie add on the harm balancer another 10 degrees. Do this three more times until you have 50 deg total around your harm. Balancer. Darken the 10 20 30 and so on marks so you can tell them from the others marks.
Get the engine to run at whatever idle speed you can achieve, the slower the better with the vacuum advance disconnected. You could use zero for the timing setting although it might not run at that. Now with your tach and Timing light note what the distributor gives for advance at idle. Then starting 1000 RPM and going up to say 4500 RPM in 500 RPM intervals use the timing light to note the actual advance. You can do all this with the car standing in the garage in neutral. If you used 6 deg static as a starting setting then subtract 6 deg from each reading. This will give you the actual centrifugal advance curve for your distributor. With a modern carb this is the only part of the dist. that provides advance with the carb a wide open throttle.
While others may have a different opinion, with a stock engine and a 2BBl you probably need something like 40 to 42 Deg total centrifugal advance. Also Y's seem to like a little more than the 3 or 6 deg static advance specified in the manuals. Assuming that you want 42 deg and you want to set the initial advance to 10 deg instead of 6 deg you should have something like 32 deg centrifugal advance built into your dist. It should be all in by 3000 to 3500 RPM.
The vacuum advance adds to the centrifugal advance at part throttle. At wide open throttle the vacuum signal to the distributor is near zero. Vacuum advance is harder to measure and dial in. Basically you need to put a vacuum meter on a tee between the carb and dist. Then with the car driving on the road you need to listen for knock. The engine speed should be in the middle of the normal range say about 2500 RPM. If it knocks note the vacuum reading. Then working in the vacuum canister, reduce the advance at that particular vaccum reading. This is trial and error and pretty hard to optomize because the engine must be under load to get it right. The main problem with just retarding the dist when you get knock under part throttle load is that you also retard the centrifugal advance mechanism which hurts wide open throttle power.
It is really a lot easier to have someone with a distributor machine do all of this.
Doug T
The Highlands, Louisville, Ky.
