My "new" '74 Duster- or why I need a project like a hole in the head

What does a 4'5" backspace wheel interfere with in front? There is a guy near me selling a complete set of Year One 17" Rally wheels with Conti tires-17x9, 5" backspace, 275/40, and 17x8, 4.5" backspace, 245/40.