I have now weighted my extra flywheels and added them to a chart with the 1963 parts manual listings. I now noticed that the 1963 4bbl and 1962-3 Jetfire automatic transmission flywheels are the same part number. My non-Jetfire manual transmission flywheel is 2# heavier than the probable Jetfire flywheel John Sage has. Not a surprise, as the flywheel for the 10″ Jetfire clutch has a slightly thinner lip to allow room for the clutch pressure plate mounting 9-1/2″ vs 10″.
