Distributor advance springs
You can easily CHECK to see if they are working. First remove the cap and "spring" the rotor CW and it should move CW with "a little" force and then freely spring back. You can check the advance rate and amount with a timing light. If you do not have a "delay" light (one with a knob that shows advance) you"ll have to "degree" the balancer out enough to use a regular lamp. Do you have a 74 manual? if not send me a PM. Otherwise look up the specs for the distributor in the 73 manual, "close enough" and understand that those are published in DISTRIBUTOR degrees which are 1/2 what CRANK degrees are