I was not around at the time, so I can only guess. I venture that folks willing to put up with the lower fuel economy and the need for premium fuel of the four-barrel big blocks would have gone full-hog for the 440. But that is only my guess.
In the case of the Polara, it must not have helped that the 383-4, even though it was listed in the dealer data book and in the ordering information ("code guide"), was not even mentioned in the sale brochure (the snipped below was taken from the @ceebuddy 's great fuselage.de website):
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If memory serves, @CBODY67 @saforwardlook and @Davea Lux have previously commented on this matter -- and they were around, working for Chrysler or a related company. Perhaps they could chime in?
Most vehicles sold back in those days were appliances to serve growing families where low price, value and good fuel economy were paramount for the bulk of customers. Performance upgrades on large vehicles were not high take items. That was more reserved for the B & E body crowds that were interested in the Rapid Transit System vehicles.