As an added protection against car theft, the distributor breaker arm spring is now riveted
around the breaker arm spring stud (see A, Fig. 588), the thickness of the head of the stud increased and the stud case hardened.
These changes add two more parts to the breaker arm assembly, namely, breaker arm spring A-12169 and breaker arm spring stud A-12157.
To install the new breaker arm assembly, it is necessary to remove the breaker plate assembly. This, of course, will necessitate retiming the ignition.