There is not timing tape made for a Y block. Both the diameter and width will be incorrect. As such, I think it is best to measure and mark the damper by hand.
If you would rather try a tape, I think a 6 3/8 diameter tape will be closest - I don't recall the diameter of the damping mass at the moment. You can get that tape at places like Summit, Jegs, etc.
Lawrenceville, GA