Had this same crack on my block, it went all the way across to the valley. I bottom tapped it as far down as I could then filled the hole with JB weld and found a rubber o-ring to fit tight over the stud and trimmed out the gasket so it just fit inside, torqued it up while it was wet and it worked well with a Felpro gasket for years,just did it again with Cometics but haven't fired it off yet to see if it works.