Your hood may have the holes in the frame for the scoops. . If so locate the holes in the outer sheet metal by putting a bushing or socket with a hole in the center in that hole. Center punch the hole from the inside out and drill them 3/8's. Once these are drilled set the scoops studs over the holes in the top of the hood. This will located the other studs.
I use to use a 3/8 socket the same size as the holes in the inner hood frame then use a 3/8 transfer punch through the socket to center punch the hood. Then close the hood and re-center punch down and drill them front the top of the hood. Most all 71 and 72 hoods have the scoop holes in the inner frame for twin scoops. If you locate the center of them you don't need a template.