I have a 1969 Camaro with a 396/325 engine that we believe is all original and has a documented 41,000 miles. Over the course of this summer it seems to have developed a slight tick. I had it looked at and one of the lifters is weak or not getting enough oil and is creating the noise. We pulled the valve cover and it seemed that there wasn't much oil coming up from the pushrods. I don't believe the engine has ever been apart and judging from the condition from inside the valve cover it very well could be all the original lifters and never cleaned. The question is, should I add in some sort of additive into the oil to see if it would clean the sludge out a bit? Could that help the ticking noise? Sorry if these are dumb questions, just trying to learn a bit more about the