A high idle will start the centrifugal advance curve. Don't re-set the timing as you have to fix the idle first. The vacuum hoses to the distributor are supposed to be disconnected while setting the base timing.
Check for vacuum leaks all round. Pinch the hoses to the heater controls and the brake booster to confirm the engine isn't drawing air from them. If all of that seems fine, and the idle speed screw (small brass one in the intake manifold at about the 11:00 position) is seated, then the decel valve in the throttle plate may be hanging open. Remove the carb and solder it shut.