Ignition timing, and cam timing are two different animals.
Ignition timing, set by rotating the distributor, controls when the spark plug fires. Timing is done by using a timing light, as described above, or by using a vacuum gage. Personally I think a gage is the better method.
Cam timing is used to control when the valves open and close, in relation to the rotation of the crankshaft. This is done using a timing chain on our motors, a gear drive in the big sixes, or a belt in newer engines. However they all do the same thing. The chain, which is located behind the cover which is directly behind the harmonic balancer and water pump, connects the crank to the camshaft. Timing is accomplished either by lining up dots on the two gears, or by using a degree wheel and various other tools. Degreeing is much more accurate.