'A-Body Showdown' ~ 1967 Dart GT 273/235 HP vs. 1968 Dart GT 318/230 HP

Anyone know why Chrysler limited the 318's, with the exception of the 80's models, to just a 2V carb?
was this engine designed from day 1 as an econo power plant?

Chrysler Strange Decisions

The 318 4-Barrel was available in the Marine Application

With a........ 318/240 HP