I have been researching my 400 engine block as follows: Stamped Block code: WW Stamped Production code: 0719693 Casting # 9790071 Date Code: D309 Stamped VIN code 29X155150 Please correct me if I'm wrong on any of these, but WW is the 1969 RAIV 400 cid 370hp, built April 30 1969. The "X" in the VIN denotes the KC Kansas Assy Plant (the VIN stamp is not very deep and onlyby g90g00huff - Pontiac GTO Forum