This looks good on a '66 coupe. Replaced nuts with 1/4-20 x 3/4 Stainless Steel bolt, stainless steel split washer, stainless steel washer, then rubber washer (all from Lowes), much easier to install. Holes will come through into bracing area, cut tool access holes in brace. <1hr job, looks really awesome. (Get a hood scoop, too...) Too heavy for trunk springs, doesn't really sit totally flat, these could probably be easily fixed for those who are picky (body filler, and a modern-car lift strut to assist, or some such).
This wing is the poor mans answer to the overpriced go-wing. I love it on my 74 Charger