I'm in the process of installing a roll bar in my 73 mach 1 right now. It's a Competition Engineering 8 point bar, however I'm putting it in as a 6 point. So the main hoop, the 2 rails going to the trunk and 2 bars going to the Tinman subframe connector I installed. I am not using the 2 bars that go along the doors. The back seat room with this configuration limits the back seat use. You could install it as a 4 point bar and still have use of the BS. you would need to cut some holes in the rear side panels for the main hoop to go through and 2 holes for the rails going to the trunk. You would still have a pretty good back seat area, installing the 2 bars going to the sub frames would take away quite a bit of your floor space area and installing the 2 door bars would make access to the BS very limited!