Mike,
Yes, the ball aligned with the pointer is TDC for #1 piston...this is your reference point when timing the engine with a light.
I think technically that the ball-on-pointer location is really several degrees before TDC, as this is a timing mark and not the actual mechanical top of the stroke for #1 piston.
Some flywheels have several marks, one is a timing mark while another is true TDC for #1.
I think I read this somewhere, but might be mistaken.
Stuart
