I discovered a crack in the water jacket of my Pontiac. Anyone ever fixed a cracked block with the lock and stitch method??? I think I am going to try it. You can order a kit from the manufacturer for a DIY Repair. http://www.locknstitch.com/
Pretty good pictorial of a Lock-N-Stitch block repair toward the end of this page.
Lock-N-Stitch Repair for engines, compressors and other cast iron equipment by Reynolds French