Most timing lights have three wires a positive and native that go on the battery. Then the third just lightly clamps on the number one spark plug wire. On a big block Chevy the number one wire looking at the front of the motor is on your right front. And I would keep it at 10 degrees. There is a bolt at the base of the distributor that holds a clam loosen it just enough too barely rotate the distributor. Make a mark with a black pen from the base of distributor to the intake manifold so you know where you started. And only turn distributor a hair. Have you turned the distributor? Why are you timing it? You really should have someone that knows what they doing help you with this.
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