Can anyone tell me the difference between the early/late serial# choice of distibutor caps for a 1976 450SLC? The selection is based on engine serial number and mine appears to have a factory replacement block (no serial number.) At least, I can't find anything stamped on the L/R side of the engine block.<br> <br> The electrodes in my dist. cap are wearing at the very bottom edge of the metal. That makes me suspect that the correct cap will have longer contacts or sit a bit lower on the distributor assembly.