Duster hood Scoop Placement
On a Demon or Dart the hood has access holes in the understructure that show where about half of the holes go. If you use those access to drill holes in the out skin, centered in the middle of the access hole, you get enough holes to locate the scoops. Once that's done you can use the scoops themselves to locate the rest of the holes. I would imagine that the pre-'73 dusters had access holes in the understructure as well?
I used a template to drill the hood for my Demon, checking against the access holes in the understructure. I'd offer up my template, but I'm planning on adding scoops to my Dart also.
All assuming you're talking about the dual hood scoops, not the later ones mguner shows.