FFCobra Master Craftsman
My favorite mod was done by Inman Lanier while he was building his car, FFR #1189 four years ago. Header contacted foot box just where you mentioned. He put extra rivets all up and down the footbox aluminum seam, then beat the tar out of it that interfering corner with a hammer. Clearance was instantly made ample, footbox remained intact, and you don't notice the mod unless you're looking very close. Heat's never been a problem, so no extra insulation. Inman's a racer, works with an entirely different mindset than some other builders. His attitude helped me get my car, FFR #1152, together and out on the road a lot faster than I would have otherwise!