Both marks on the gears at 12 o'clock is #1 firing position. Crank gear mark at 12 O'clock and the cam gear mark at 6 O'clock is the #6 firing position. Do you have the vacuum line to the distributor disconnected and plugged? Do you have the timing light hooked to the wrong wire buy mistake? Is the timing light a dial back model? Try a timing light with out the dial back feature.
