I installed a factory original RAIII setup on my '69 Goat. All it was missing was the scoops, heat riser, heat flapper, foam seals and one cable. Got it all for $500. The factory flapper door bracket mounts to the back of open hood scoops, so hollowed out closed and extended scoops will not work without mods. I cut my hood braces myself a little at a time. The cut is to clear the flapper door assembly, and cannot be seen with the upper pan in place, so no worries if it is not perfect, mines not. I bought aftermarket plastic RA scoops, they fit the hood good, not great. The mounting studs on the bottom broke off very easy, but the flapper assembly kept them in place for years. I used fiberglass filler and mat to cover the heat riser holes in the upper pan because I an not installing a heat riser system and didn't want any hot engine air to enter, plus I am running headers.I also fiberglassed over the factory breather holes in the lower pan. I changed to a 14 inch filter from the factory 13 inch, different lid painted black to match. Hope this helps.