Compare the door shape with the B8, the B8's are much flatter and do not curve round into the windows as much as your mystery car. The windscreen shape is also wrong, the B8 leading edge is very much bowed forward. All B8 front clips came with recessed headlamp openings. The sills below the door ran the length of the chassis at a constant height and were made from sheet steel curved over the chassis tubes. The front and rear clips came down to meet the sill in line with the door bottom. The cockpit rear bulkhead in your picture appears to be part of the body, on the B8 this was formed by vertical aluminium panelling over the chassis tubes for the upper half, the lower half sloping forward to the floor, made of sheet steel welded to the chassis frame to cover the fuel tank. The window opening in the rear bulkhead is too wide and not deep enough to be a B8 which also has square corners. As regards gull-wing window openings or door cut-outs into the roof I have never seen or heard of that on any Chevron. Good luck with your search!