The octane selector is a throwback to the 30s and 40s when gas quality and octane were all over the place, and driving at high or low altitudes required an adjustment. The plate allowed some easy adjustments and a hard stop at 10 degrees advanced or retarded to compensate for the bad fuel or altitude. With today's fuels, you don't usually make those kinds of adjustments.
Now, if you look at the octane plate and the clamp you will see that the octane plate is held down by a bolt and the distributor is secured by a clamp and a screw. The screw is what you use to set the timing, not the plate.
So ideally, you want to set the octane selector plate at 0 and set the timing using the screw clamp arrangement. You also need to know what the factory recommendation is for the timing on the motor you are using. Usually, when you see UIC on the flywheel, the bb is set for some amount in advance which is also marked on the flywheel. So if the flywheel is marked 5 degrees and has a bb, and your motor is supposed to be set at 5 degrees advanced, you set it on the bb, not TDC at the UIC mark. If your motor is specified for TDC, then UIC is fine. I have actually never seen a flywheel that is marked with UIC and no bb. All of the TDC flywheels I have in my stash are just marked with a bb for TDC. So, Disconnect the vacuum advance and plug it. Set your timing, then reset your idle speed if its lower or higher then it should be. Adjust your idle mixture screw, readjust idle speed if necessary, recheck the timing.
Last edited by Dragsix; 10/28/2019 7:15 PM.
