It's block casting number '53'. Ran from 98.5 to 2001. It is stamped on the block in a couple places. I believe on the passenger side and some where in the front but the one on the side is easy to see.
My buddy (with my help) got Cummin's to warranty the block he had and ANY internal parts that might have been needed plus they supplied all gaskets.
Cost him labor. He was at 100,000+ on miles not sure how much help you might receive but it would be worth a shot if it's a leakier. NOT ALL leaked or cracked. Blocks were from Mexico that were effected. Not looking to rain on your post ,sorry.