I recently sent my 3 GBD cylinder heads to Henry's MM Engines in Bakersfield to have the valves ground. They pressure tested them and they were all OK, however they found two of the heads had cracks near the valve seats. They said they had an engine in there back lot that might have two good heads, but as it turned out they had cracked heads too, so as a last resort they mentioned that I might be able to get the heads "lock stitch" welded but weren't sure if it work on diesel heads. Has anyone had experience lock stitch head repairs. On another forum two individuals said they were running a diesel five star and a Vista with cracked heads and it was not a problem.