So I am rebuilding the top end of my ‘91 Z28 because I bought her with a head gasket issue. I’ve removed everything down to the heads but not the heads yet. Doing so tonight. Inside the two rear passages in the heads there’s a complete blockage of a hard white/yellow material(almost looks calcified, I’ll link pictures). I wanted to know if anyone knows what it is and if it’s a serious problem. Or can I just scrape it out, send the heads to a shop to be cleaned, and be on my way to rebuilding?

 

10,000 years of tap water

 

LOL - good one Sofa.

 

lmao thank you
so I take it it’s not a big problem then

 

Nothing you can't clean out with a short piece derived from an optional muffler bracket.