not good

1968FormulaS340 said
If you can easily open the valves by pressing on the springs, your springs were done years ago.

Probably floated the valves allowing that pushrod to jump loose and get beat up.

I had a chev 350 that had springs that were so dead that the valves would float at 3500 rpms.

I agree with this possibility except It should have been obvious that after "getting on it" a miss developed. It would have been instant. I guess pulling the head is gonna be necessary.