TDC on the flywheel is the vertical line between the U|C.
The "ball" is where the manufacturer wants timing to be set at a very low RPM with the vacuum advance disabled.
Unfortunately my flywheel is new and has no ball stuck in it.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
