Generally, the YBlock timing marks are in two degree increments. The first s/b top dead center. I have found that Y's generally run better anywhere from 6 to 12 degrees advance. You can experiment with this.
Best to make sure that the ring that has the timing marks is in the correct position. Over the years the rubber holding the ring is known to deteriorate and the ring slips and slides .
Get the engine at top dead center on the compression stroke (both intake and exhaust valves on #1 cylinder are loose and the rotor points to the #1 contact on the cap and see how things line up with the mark on the damper.
