HELP Engine diagnosis

[Daca214]

Ok guys with my introductory post in the books im going to dive right in and ask for assistance!! Lol
For those that may not have seen my thread on my regal over at gbodyforum i ran into an issue with my motor
It was clacking really loud. Anywho long story longer i started tearing down the top end and it was spotless. Thats when i discovered it was rebuilt ans bored .040 over.
#8 cylinder was the source of noise and i saw the pushrod looks like this

Have you guys ever saw a pushrod wear like this? What would cause that? Bad lifter?
It literally looks brand new in there

Heres some more pics.
Any help as always is greatly appreciated

 

[Olds 307 and 403]

Olds 350? What heads? Ouch, the big dish pistons, makes for very low compression. I never seen a push rod wear like that, it could be improperly hardened. Make sure to check the bearings as well. A better piston in the 4.100" bore would be a huge improvement.

 

[Daca214]

Olds 350? What heads? Ouch, the big dish pistons, makes for very low compression. I never seen a push rod wear like that, it could be improperly hardened. Make sure to check the bearings as well. A better piston in the 4.100" bore would be a huge improvement.

Its actually a 307 with 5A heads
I was hoping to not have to tear the bottom end down but i guess thats the only way to reall know whats going on right

 

[Olds 307 and 403]

Yeah, double check it all. A small performance cam might be a nice upgrade while it is apart.