I have a 70 Chevelle with a 396 that I am beefing up and don't want to keep the stock lap belts. I would like to install driver and passenger 5 point harnesses without a roll cage, but can not find info on how to actually mount the shoulder straps. I keep reading not to mount them to the floor. Is there a way to do this properly and safely? If not is it possible to install a roll bar/cage and still have access to the backseat. This is a family car and I love cruising with my son in his car seat so if anyone has any advice I am all ears.