SimonBolivar,

The initial adjustment timing setting is different for different year engines.

Also, different year flywheels have differerent marks, including a ball, line(s), a triangle - usually at least a ball is there.

Here is some information on the timing mark for various engines/years. Please note that a flywheel from one year might be found on another year's engine:

http://www.secondchancegarage.com/public/468.cfm

http://www.secondchancegarage.com/public/468.cfm

Once you know you have the distributor installed correctly to fire the #1 cylinder on its compression stroke, and you have the plug wires in the proper rotation-order, you can use the ball or just about any other nearby mark as the initial/rough timing mark (to get the engine to run and rough idle).

Once you can get the engine running/idling, you can fine adjust the timing setting by using a few other techniques (highest vacuum reading at 2,000 rpm, or a "no ping on load adjustment").