143 Tooth Flywheel is the 11" I think, and the 130 Tooth is the 10 1/2"....Flywheels are different as are the clutches...If mismatched, the starter won't even engage the flywheel...
If you get the cast, you will need a 318 "truck" 11" flywheel to make it work..If you buy the aluminum one, you will need a 10 1/2" 318 Car/truck flywheel...