Quote: Broken intake valve spring is a possibility. The dampener and reminants of the spring would keep the valve closed and operating at starter speed. or turning over by hand.
Then when you run it, it'll bounce. Push on the rockers by hand. If you can move a valve up and down, you know what it is.
FWIW, I've seen it more than once.
I think this may be it!
I pulled the drivers side valve cover whiel the engine was hot and pushed (with a glove on) on the rockers- I could get almost ALL of them to move atleast 1/8 of an inch without too much effort.
I have exp with cehvy but this is my first Mopar engine. On a chevy you cant push springs like that. If its the same on the Mopar then we may have found it.
Is it the lifters that you are getting to move, or the valve springs?
Its for sure the spring/valve moving. not the lifter. the valve is closed and I push on the rocker above it and it pushes the valve open