Timing

[Hugh Mongus]

I went to Sears today and picked up an advance timing light. I turned the dial to 36 degrees, had my wife press the gas and hold it at 3000 rpms, and set the timing to 0 degrees. This left me with around 18-19 degrees initial timing. Since the advertised timing for a 350 is between 8-12 degrees, should this tell me anything?

I have no idea what's inside the engine. It has been idling rough, idling rich, and fouling plugs in a couple of cylinders. It runs great, but gets poor fuel economy.