On a 4160 Holley (vac sec)
There is still a spring kit of 10 different springs to adjust the opening rate of the vac sec diaphragm
I've seen 750 , 4160 's tuned with the springs that you could barely detect the opening of the secondaries
It is slightly oxidized bronze dizzy gear for use with a steel billet camshaft, and is considered sacrifical
I have never seen steel or iron with a golden finish, unless plated