The link with the photo of the drill angle is great information. One question: if the hole is drilled slightly larger than the steam holes found on the head gasket...will there be any potential head gasket leak or other concerns about that? Someone at one point drilled into the 848 head on my 261 and the holes are slightly larger than the gasket holes and slightly offset.

I'm thinking that by following the correct tightening sequence and ensuring that the spray copper head gasket sealant is applied properly aroud those holes...that there shouldn't be a big concern. ?

Thanks in Advance. Tom

1946 GMC Project
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