The big difference would be with the prop rod style! The 64-5, and some early 66's had the ratcheting slide bar prop rod that would've been mounted on the passenger side, and there would be a bracket welded to the passenger side! The later 66's had the slider spring tube which had a hole drilled into a flattened land on the drivers side, with 2 smaller screw holes for a retainer bracket! Hope this helps, Geof
