The fabrication is much like Jeff's as far as the knee bar and door bars except I located the forward end of the doorbars at the floor, welded to the base of the forward halo down bars. I have a diagonal in the main hoop, a harness bar, and overhead diagonal in the halo. The harness bar allows you to add a back brace for your aluminum seat. The seats are mounted so that the butt contacts the floor. I like to sit low.
I used 1.5" 0.120" wall chromoly. Because of the limited space in the cockpit, because I didn't gut the doors, and because I wantto be able to fit one of Bruce's Lemans tops over the cage, it is a compromise. It's compatible with the wind screen.
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BobSchoeni
FFR 347ci