Valve guide boss cracked

4spdragtop said

Doing my DIY port and gasket match and spotted this on #4 intake. I read that you can take the boss and valve guide down about a 1/4"? I dont know if that will get rid of crack or not. Suggestions?
Thanks
Steve

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Hey Steve,

That crack looks to be all the way through the casting. If you just leave it, Temps/vibrations etc .. will cause it to spread even further, maybe even change direction the same way a crack in a windshield can migrate all over the place. The real fix is to drill or grind out the crack completely and fill it . Find a shop that can do cast iron welding and fix it properly. Or, just find another head.
My approach to problems like this has always been... "How bad do you want to take it all apart again to do it the second time? "