Off idle hesitation - solved

Besides having a 2 bbl Stromberg WWC carburetor, other things are much different than a 1966 slant. I doubt due to Canada. Yours has an EGR intake manifold, which I don't think was until the mid-1970's. Even California cars with the Clean Air Package in 1966 had only a few additions like PCV w/ breather tube to air filter. 1966 slants also had a rotating throttle rod, rather than a cable. Your throttle cable bracket looks perhaps custom-made.

My 1965 Chrysler Newport w/ 383 had a factory 2 bbl Stromberg (Bendix) WWC carburetor (replaced). If someone retrofit that on a 1970's Super-Six 2bbl intake manifold, your engine would be way over-carb'ed and idle poorly, giving poor mileage and smelly exhaust. You could check the carb PN against a C-body and see if yours is too big. Super-six engines used a Carter BBD carburetor, which was also common on small-block V-8 engines (different PN). You can buy new Chinese knock-offs for ~$100 (ebay), but insure with the Mopar throttle connections since many manufacturers used a BBD.