I wouldn't say "leftover 426 Wedge" engines; but rather, they were indeed available, but just not publicized at all. I've never subscribed to the belief of "leftover parts" because parts that were still on the line, especially if they were not for the coming models to be built on the line, were simply put into the Chrysler parts system for use as warranty replacement parts as well as over-the-counter sales. Corporate bean-counters would never have put up with the inefficiency and budget problems that "leftover parts'" would bring! The 426 Hemi was highly publicized for 1966, of course. If you had the customer that said "Damn, I'd love the Hemi in my new Coronet/Charger, but I don't have the $$$ to afford that!", the savvy and knowledgeable salesman would say "Hey, I know it's not in the brochure, but we can get you a 426 Wedge engine for the cost of a 383!"...I believe that is the overall scenario that put the 426W in a few Coronets and even fewer Chargers for MY1966. Certainly, a dealer-installed 426W would likely have been the likely outcome for the Charger, given the car's mid-year release date.