That is the worst example of a snorkel scoop I have ever seen. A 73 Dart Sport scoop fits without any mod to a 1969-1972 Valiant/Duster hood. There are some nice repop scoops out there . That is definitely not one of them. I have seen them on some cars and they are smaller in size then the factory scoops. Here are a pictures of a factory 73 style on my Dusters.
I just got another hood given to me with a 72 style scoop mounted last week with a collection of parts. They cut the lower piece to fit the hood but to far. I have that hood on Face book if you want to see how they cut it.
On my Duster hoods I copy the Demon placement for the correct placement for the holes in the inner panel. This puts all the studs in the correct location. The first picture the bottom scoop is a 73 style as are the scoops on the cars.