What parts needed to change 73 nova to 74 nova?

To convert a 1973 Nova to a 1974 model, you'll need to change several key components. These include the front grille and headlights, as the 1974 model features a wider grille and larger, federally mandated headlights. Additionally, the rear taillights and possibly the bumpers should be updated to match the 1974 design. Minor adjustments may also be necessary for the interior and emissions equipment to comply with 1974 regulations.