Hey everyone I have a 2000 Silverado 2500 ext cab short bed 4x4 4l80e 6.0 with cast iron heads. In the past I had a exhaust leak for a lil while drivers rear, like everyone else I had broken bolts. So I was able to replace them all, two were flush with the head, let me tell you PITA!! but manageable. So I had put it back together but never resurfaced the manifold before putting it back on and used those compound gaskets. Anyway sometime later I had some muffler issues and support problems and long story short had a pretty bad leak after a while same spot. Had to park it for a while. Then took off manifold and it's definitely warped and when I was in there and noticed some fluid leaking from the ports where the exh leaks were, definitely not the valve cover. I was curious so I actually tasted the fluid and it tasted like fuel which is somewhat surprising but a little expected. I guess if I had a misfire and fuel wasn't getting burnt that's possible but to get to the point. I noticed some fluid that looks like oil on the base of the valve guide I'll post pics. Thinking about doing a valve seal job with heads in place but not sure if the leak was just sucking all the oil to that one spot and thus carbon built up around the opposite side of the guide which makes sense. Didn't know if I could get away with cleaning up the guide and fixing the exhaust leak. I suppose it's possible that it was a mixture of unburnt fuel and oil slowly leaking. Anyway I'd appreciate any help with this.

 

FYI idk why the pictures got flipped upside down sorry

 

That's what I'd call it, valve seal leaking