were spark plug wires the same for all slants

They will fit between the years, no major changes. Only difference is electronic ignition and the change to silicone insulation, wires are still interchangeable. The spark plug boots changed a little when they did away with the spark plug tubes, I believe this is when they went with Hydraulic lifters (not certain). Anyway, wires will still fit. I have 1979 Volare wires on my 65 Belvedere and no one can tell.