When I assembled the C8 cab, I discovered that the drivers side arch bar was twisted out of alignment - meaning that the drivers side wing would not sit level so I had to make up a small adjusting mount for the wing . How this twist in the archbar happened is a mystery , it must have been made like that .
You could see where somebody on the production line had beaten the inner fill in panel, to make it fit the arch bar . Being a very early vehicle, I guess the first batch or two were not fitting together as they should have done