Hi, I was just wondering what this hole is for? Could this be a little bypass? I have a BB with the bypass hole on it already, will this hurt anything? thanks, Eric

Are you talking about the holes to let the air bubbles out.

I guess it might be, not sure

That's a good thing. Saves drilling one yourself.

Yup, I usually put a small 1/16" hole in manually. Great for "burping" fresh motors when first filled with coolant

Awesome, I got this from ACDelco for my BBC. thanks guys, I didn't know that, Eric