The grey was very similar between assembly plants but they all mixed their own engine paint and that led to slight variations.
The engines were not painted at the assembly plant, they were painted at one of the two engine plants, Flint or Tonawanda and then shipped to the assembly plants
Chevrolet did have a paint code for the engines, it just wasn't made public because no one else needed to know it...not because it was a big secret or anything like that.
Mike B
