Nice looing design... the side bowed out hoop is a good design.
Seriously... This "ROLL BAR" in the pic's would not sustain a roll over 75 - 85 MPH... in my humble opinion. (The Horizontal brace that attaches to the B-Pillar Seat Mount) would take about 1/2 of the blunt force of the impact in a high speed "Roll Over. Please find pic's of one I built in 1970 1/2 (Z-28) & another one I built in 2015 on a 86' (951)
1) You would need (2) (extra) (Solid Bars) (Not joined together with welds like in your last pic) in the center going from the top of the roll bar to the (Hoop) floor mount bar or going to the rear seat belt mounts.
2) (2) extra center braces going from the harness bar back to the seat belt mounts.
3) To be on the safest side of (NO) failure... I would install 3" (Tri-Gussets (3/16" thick) at each point in all the bar attachment points and very large 3/16" thick (2) (8"X 8") floor bolt in brace under the main floor.. (the main floor is the weakest place in the car to withstand a high speed roll over).
Just (MHO). I have raced in NASCAR, Trans Am, SCCA & IMSA GT and have built many a sway bar.
Ron... I wish u all the luck in the world in your design... "Looks Good"!
