I talked to my friend and Dodge engineer ('62-05) who was in charge of Dodge engine development during the time about why no '72 3x2 when the brochures and a few examples somehow were made and at the last minute the 3x2 440 was dropped. He said because of the 2-year phase-in for the evaporative emission standard or EVAP ( 2-year phase-in from '70 had to be completed by model year '72) could not get done because Holley would not modify the front and rear 2-bbl carbs with the necessary captured float bowl venting. He said they did the in-house modifications tested them and then submitted them to Holley and Holley turned them down. With that and all of the other models that had to come into EVAP compliance during the two years since the '70 regulation (remember the '70 models with the vacuum butterflies on the air cleaner snorkels and the vacuum hood scoops, the charcoal canisters, gas tank vent bottles, etc. yep EVAP) Holley had no time to mess with multi carb Chrysler engines. So if you asked me why no 440 dual quad in production after only three years of a 440 3x2 I'd have to say the same reason for no 72 3x2 or any multi carb engines from that '72 date forward. The SIX PACKs enjoyed some healthy sales from '69-1/2 to '71 and spending more time and money to make a 2x4 anything for one or at best two years made no sense at all to the bean counters, marketing and the engineers. EVAP and all of the other EPA/CARB emission standards and then add in the gas crunch just try and sell the idea of a 2x4 (8-bbl) massive 440 cubic inch V8 for an on-highway vehicle (car) to the powers to be. Just look at all of the crap, development and money that had to go with and comply with EVAP and all of the other emissions regulations at that time and how it affected the cost of the car. As stated, "it's all about the MONEY $$$$$$".