Welcome aboard GoBoysGo...
X3 on adding an oil additive to possibly help with a "sticky lifter". It used to be pretty common back in the day. Because of it's high detergent qualities I used to use auto transmission fluid, like Dexron. Add 1 qt (don't overfill, drain out a qt if needed) and when the "clicking" stopped run it another week and change the oil.
This was very common 50 yrs ago and guess what? Your engine was designed and built about 50 yrs ago...
Best of luck, adding a can of miracle oil will not hurt your engine. Give it a try after checking all suggestions above about wear, etc.