exhaust valve to bore crack

[AdminGuy]

I have this common crack on a few barrels. I was told to just run them after bore and not to worry about it. What is the procedure for repair? Drill it out and weld it up. Then bore and maybe valve seat insert.

Do you know anyone that has done this? Fixed these barrels?

[AdminGuy]

One of my guides was wielded in. On, in place, whatever. Is it possible to weld and rebore the guide hole? Any thoughts on fixing this? A shim?