Valve train noise

When valve train noise first starts showing up, first thing to check is the oil pressure.

Low or no oil pressure, lifters won't pump up and yes then they all make noise.

Put an oil gauge on it to see where you are at, idiot light may have burned a bulb after 50 years not warning you of the problem.

Plugged oil filter, plastic timing chain gears coming apart an getting stuck in the oil pickup screen.

Rods and Mains and Cam bearings getting wore out not holding pressure anymore.

Cam going flat from running old mopar engines without the recommended zinc additives in the oil.

New oils do not have the zinc in them. Needed for the early flat tappet cam engines.