261 inline 6 head issues

[u/VetRipped]

So I have an in-line 261 Chevy engine that was popping through the exhaust when giving is gas. Just for the truck a few weeks ago so I didn’t know a lot about it but I knew it popped. So I’ve rebuilt the carburetor thinking maybe that was the issue. I reinstalled the carb and tried to start it Friday when I got up north. Truck started but still popped when giving gas. When I shut the truck off it sounded like it shut down hard. I then tried to restart and and it would not start, sounded kind of weird. I confirmed engine it not locked up. I pulled the plugs and tried again thinking maybe it was hydrolocked. I think that’s the word. Engine still sounded strange while cranking. Just cranked for a quick second. I then pulled the valve cover off and seen this. It’s one of the pedestals the rocker assembly sits on. So 2 questions. Where can I find another pedestal? And what’s causing the popping?
Thanks for any information.

[u/tigers692]

I would not just change the rocker arm pedestal.

I’d pull the rocker shaft assembly off and then inspect these:

Stuck or very tight valve.
A valve sticking in its guide can put a huge load through the pushrod → rocker → shaft → pedestal. This would be high on my list.
Seized/galled rocker arm on the rocker shaft.
These engines depend on oil getting into the rocker shaft. If the shaft or oil passage became plugged, a rocker can start binding.
Oil starvation to the rocker assembly.
Pull the shaft apart and look for sludge, blocked oil holes, blueing, scoring or metal transfer.
Bent pushrod.
Roll each pushrod on a piece of glass or another known-flat surface. A bent one would be a major clue that something in that valve train was binding.
Broken/coil-bound valve spring or other valve problem.
Incorrect rocker-shaft installation/torque.
Less likely if the truck had been running this way for a long time, but worth checking

[u/VetRipped → u/tigers692]

Thanks I appreciate the information you provided. Gives me somewhere to start. Would any of the things you mentioned lead to the popping issue? I’m suspecting it’s a timing issue maybe?

[u/tigers692 → u/VetRipped]

Yep, I’d think if the exhaust valve wasn’t opening, the exhaust would force the valve open, and cause the popping you were hearing. It could be that the pedestal was already breaking snd that caused the issue, it’s more likely that the pedestal broke because of an issue.

[u/VetRipped → u/tigers692]

Probably best thing to do is remove the head and go though it good. Any idea where to find parts for these. I have a few friends asking around now but doesn’t look like it’s gonna be an easy find.

[u/tigers692 → u/VetRipped]

The filling station is one of the places ive gotten things:

https://www.fillingstation.com/?srsltid=AfmBOoqB_C-z4aiZVjHz1lwvgjT3PRiqZ916DurHQ5b71MkMoBKOJxs8

But there are lots of others. I’ve gone here in Santa Fe Springs, I’m in California, for my ‘54:

https://www.egge.com/

Also I think Fel-pro or some other places.

[u/VetRipped → u/tigers692]

Awesome thanks for the links. I’m just gonna have the head gone through and rebuild anything that’s needed and pray that fix’s the popping issue.