I have a couple of 340 hoods at home, and I will measure the openings. I think it is 4-1/8 off top of head. I will also take some picks of the factory 72 340 Demon cutouts which are off course different. AFAIK, even my non-scooped Dart hoods have the underside holes, will double-check that as well. Also, I don't think the dual-scoop setup used on the Duster (Twister?) were functional, so there may not be any attaching points. As a point of interest, I am sure that all 73-? Dart hoods have the underhood locators for the 69 simulated scoops. Same stamping.
Grant