Mike, Indeed you are correct. Its a match to the front opening, much like the customs of the sixties. It turned out really well, I was surprised at how it mimics the front openings much better than a half-circle radius job. The customers tire is a 29 inch tall, by 12 inch wide give or take a bit. I drilled extra mounting holes in the front perch, to assist in lowering the car down to adjust squat, as the Calvert springs sag very little over time, usually not more than 1/2" inch. But with the template, you can ""creep"" it down, and not make the opening as tall. I did have to manipulate it a bit with freehanding, to blend in the front opening to make it wider. But- here is the great news! It was EASY! All you have to do is get a large piece thick paper, tape it to the opening, and use you fingers pressing against the edges to transfer the opening to the paper. Then, just go back and line it with a pencil, cut with a razor blade, and you have an instant template.! This is the same method I used when I had access to one of the remaining Hurst Dart's, to make a template for their back openings so I can replicate them for customers.. If you need me to fill in any questions though, I'd be glad to help!
Dale
