Mystery 396 casting date

[indyjps]

GM typically has their annual shutdown the first 2 weeks of july. i cant guarantee that happened in 1968, but if the car was built over the shutdown in 1968 and built during overtime there would be a high likely hood that the operators were not the "normal" operators @ each station. overtime would have been run on seniority. so the likely hood of having an inexperienced person @ the stamping station could have resulted in the numbers not being updated. just a thought.