@Wild one has mentioned this as a possibility more than once, weak valve springs.
So here’s an interesting question/thought. Watching all the “YouTube’s” about this change everyone says “soak the lifters in oil for a day but expect lots of clatter when you first start it. This will last 10-30 minutes as everything fils with oil.” Some of them even rev’d the engine during clatter stage to try to hurry it along.
Holy guacamole… that is a lot of hammering of empty lifters against poorly lubed cam lobes. Did dodge do it this way “back when”? That could have caused lots of random damage depending on who was running the throttle during start up.
Or, did they have a solution to prefill the lifters/push rods?
I decided to try something I haven’t seen before: I used a vacuum pump and vacuum tank and put all the lifters and pushrods in a bucket of oil in the system. I pulled -28” Hg of pressure for several cycles then on the last cycle let the pump run until no more bubbles came out. This guarantees that every new lifter and every push rod is completely full before I start the system. I also plan to do a no-start crank until oil pressure before letting it actually start.
I’ll let you know tomorrow how it goes.