The stock pickup is designed to have the shield on the bottom touching the stock pan. If you need .200 gap at the pan to block mating surface something is wrong. The pickup part number you list shows for C body applications, which may or may not be the issue, I do not know what the differences are but I do know that the C body used a different pan as well.
They say there are no such thing as a stupid question. They say there is always the exception that proves the rule. Don't be the exception.
