9.5/1 comp. early 60's rebuilt 350. edelbrock rpm heads, edelbrock cam & lifters, summit stock length pushrods, crane 1.5 ratio energizer roller rockers. 1 lifter on each side seems to be bleeding down and causing ticking sound. We adjust it while running until it's good, and then about 15 seconds after it starts ticking again as if lifter is not working right or bleeding down. Have checked pushrod clearance-valve retainer clearance-have swapped lifters and same rocker keeps acting up???????. Have installed stock stamped rockers and same problem. Cam is good. Oil pressure fine.What the hell! We are stumped. Help-T

Could be any of the following:
Cam lobes wearing

Rocker stud pulling out (or unscrewing depends on head)

Rocker nut backing off (very common problem)

Plugged oil galley (does oil come up through the pushrod and dump out on the rocker?