It is always best to keep the pickups as close as possible to the face of the pickup. Occasionally the the geometry of the box, neck and bridge creates a larger distance. If possible it would be helpful to lift the pickup and cover. These spacers are made for each of the MGB flat pups. The are 1/8 of an inch thick. You can use one or more. The screws that come with the covers are long enough to handle several spacers.