8 point roll bar
This is the set that I made. I used 1.5" x 3" x .120", so that no cutting of the floor was needed. I did overlap a pretty large section of the rear rails, and added gusset plates on the front that tied into the gusset plates I already had welded around the torsion bar anchors. If I'd really been thinking I'd have made the gusset plates for the torsion bar anchors large enough to use as the ends of the subframe connectors. In the back the subframe connectors also got tied into the torque boxes. The 1.5" tubing allows the frame connectors to overlap and then sit flush with the rear frame rails, and they also sit right against the rear floor pan. Depending on what the rules say you could weld that entire section of subframe connector to the floor.
This is the set that I made. I used 1.5" x 3" x .120", so that no cutting of the floor was needed. I did overlap a pretty large section of the rear rails, and added gusset plates on the front that tied into the gusset plates I already had welded around the torsion bar anchors. If I'd really been thinking I'd have made the gusset plates for the torsion bar anchors large enough to use as the ends of the subframe connectors. In the back the subframe connectors also got tied into the torque boxes. The 1.5" tubing allows the frame connectors to overlap and then sit flush with the rear frame rails, and they also sit right against the rear floor pan. Depending on what the rules say you could weld that entire section of subframe connector to the floor.