Using LX (New Charger/Magnum/300) Wheels on a 74 Dart

Just went and looked at a beautiful set of 10 double spoke 300C wheels today (local Craig's list). Cast lettering into back of the spokes identified them as 17X7s. Answering a question asked earlier in this thread, the back spacing over the bead flange to the mounting pad was 6". Would have sprung for them if they had been 8 or 9 inches wide.