This ring gear has a 10 1/8" ID to fit the common Ford 2.0L SOHC Pinto flywheel. Some later model FF1600s also use this ring gear (the SCCA-legal JAE flywheel for FF1600 takes this ring gear).
The 110 tooth design will work with either Lucas or Tilton starters. When used with the Lucas starter, the ring gear should be installed with the tooth chamfer facing the transmission. Tilton starters do not require the chamfer and will work with the ring gear installed in either direction.
Note: Some recent British cars use a 10 1/8" ring gear with 132 teeth. This ring gear will not replace the 132 tooth gear without changing the starter.