71 Duster Hood Scoops

Is there any specs on the size of the holes? I've seen posts that say 4" and some say 4 1/8". I'm ready to buy a hole saw to make the holes but I want to make them the right size to fit the rubber grommets .

4-1/8” is the proper finished size. But if you’re making the cut with a hole saw, using a 4” hole saw is probably a good idea. I used a 4-1/8” hole saw but the holes ended up slightly larger. They’re not 4-1/4” or anything but they’re a bit larger than 4-1/8”. I think using a 4” hole saw and then cleaning up with a file and some sandpaper would be the way to go.

Your grommets look like they are in wrong. The thick part goes on top of the hood. Trust me. Or Google it. :)

He’s not using the correct grommets anyway, so that’s probably the issue.

But absolutely, with the correct grommets the tall side goes up, the goal is to keep water out.

Detroit Muscle Technologies sells the proper ones. The picture on the listing shows the bottom which is a little deceiving, but they do have the tapered shoulder on top. They fit well on my Duster (dart hood because it’s a demon clone). They’re just a touch loose on my car, they’d be perfect for an actual 4-1/8”.

Mopar A Body 1970 70 1971 71 72 Dart Demon Duster Fresh Air Hood Scoop Seals DMT | eBay