I just had this motor  built short block by a shop in so cal and the motor has only 9 hrs on it when the boat just shut off. Upon further inspection i noticed the the bronze dist. drive gear wore down and a few of the teeth were gone. Thus putting the motor way out of time and it shutting off.What caused the disr drive gear to do that? its a chevy 494 top end roller , chet herbert cam.any help thanks.so i changed my cam button on the front of the motor to a tighter spec and the gear started doing the same thing.