I did that on a classic chevy 235 many years ago. We called it "lacing" . I was taught a sealant wasn't necessary on the plug threads as rust would form very quickly and seal the joints. My crack was a long one, about 9" long. I drove the truck about 9 months after that and then used it to tow my wife's car from Texas to Connecticut and sold the chevy there. It never had another leak. The only difficult part is drilling the overlapping holes.

1956 3100 three speed 6 cyl. Stock with a few upgrades.