Can't find timing mark on balancer

Hi! I'm new to this forum. I have an E Body, and am a member of the E Body forum.
Now my son has an A Body that I enjoy working with him on.
I can't find a timing mark on the balancer. We know about where it should be, because the car runs and we have rotated the crank and have the the rotor pointed to the #1 cylinder.
72 Dart Swinger, maybe not the original 318.
Does anyone have any input on this?