factory dart shoulder belts

warrendodge You may be able to check the Federal Motor Vehicle Safety Standards for 1968 if archived somewhere. FMVSS at the U.S. DOT. I have no other information except that typically but not necessarily the DOT would make changes and make then effective on the first day of the new year giving vehicle manufacturers time to get ready to comply with whatever the change will be. You may have to verify the date of manufacture of your car as well. It should be easy enough to make and slip in a couple shoulder belt plates like I will do. As long as they are tucked up inside the roof structural web like my pic shows, then 4 steel pop rivets will be enough to hold them there for installing bolts, and they wont pull through in a wreck. Do not scab them over the visible side of the structural web. They wont hold.