Edelbrock Head Issue - Anyone else have this problem?

My car, '64 Barracuda with 340, wouldn't turn over all of a sudden. Long diagnosis story short.... water got into cylinder #7 and it was hydrolocking. I pulled the head and found where the coolant was getting in.

These heads are Edelbrock's initial release of the aluminum head for Chrysler small block, so they are about 15-18 years old.

I'd like to know if anyone else had the same issue with Edelbrock heads. I'd like to know what causes this, or was there a flaw in production. Thanks for the input.

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