1967 #391 Heads with Hairline Crack

[dlv4540]

I have found a set of matching 3904391 heads with one head having a hairline crack where the gasket goes for the exhaust manifold. It is about 3/4 of an inch long. Does anybody think this would be a concern running on an engine because the machine shop that checked these heads out said it was fine? Just wanted some opinions on this.

[the427king]

Should be fine ive had those before. drill a small hole at the end of the crack to prevent it from spreading

[dlv4540]

How much do you think it would affect the value of the set?

[the427king]

10-20% if you are selling them bare. Sell them rebuilt with a shop receipt and the crack wont affect price as much