Kadees on Lionel 21" Challenger Passenger Cars using the pre-drilled holes and the included bracket....
Kadees mounted 3/16" back from OEM drilled holes....
This were the first two cars I did. Later cars I set the new mounting hole back 1/4" and the diaphragms touch perfectly. BTW the diaphragms have a great deal of give or sponginess. They compress very easily. These are very nice cars, and with a little work (paint interior, add passengers and a few details) these cars will be awesome!