I always find top dead center on number one cylinder and move the timing marker to "O" on the damper.
If someone installed the timing marker, do you know that it is correct???? I think this is the one thing most guys miss on setting their timing.
Next I install the distributor with the number one plug in a convenient location. I make sure I can turn the distributor clockwise and counterclockwise, to adjust the timing. I install the dist. and line up the rotor with the number one plug.
Now with the timing light hooked up I start the motor and adjust the distributor till I have my base timing (10 degrees) lined up on the timing mark / damper.
If you have vacuum advance, you need to disconnect it and plug the hose. Vacuum will give you 20 degrees on top of the base timing.
If you have mechanical advance, (it should give you 20 degrees on top of the base) just adjust the distributor for total timing at what every rpm you want all your timing to come it. Say 34 degrees at 3,000 rpms.
Then there are springs and bushing in the distributor to fine tune your timing.
Dwight
[ame]https://www.youtube.com/watch?v=UYGU7mTwsZc[/ame]
Set your timing - for more performance!
I would buy a new timing light