We know where the change took place in the world of 67 Z28s. Do not want to publish this data on a public forum. I will say that not all of the first 25 cars were coded 4P. There were only a few 67 Z28s with the 4P code. Regarding the 4P L78s, the Jenkins Super Stock car was coded 4P along with the two L78 pace cars. We have not studied them as much as the Z28.