Going through what I have for the charger design and history it states that the engine was designed for light and medium commercial vehicles. Starting at 245 ci with a possible range up to 300 inches.
It's possible I mixed up some facts but the book I'm referencing was written by a former Chrysler engineer who was directly involved with the design of the Slant-6, LA V-8, 426 Hemi and 2.2/2.5 4-cylinder and was a part of the engine design department when the BB wedge was being drawn up. He also coordinated with Chrysler Australia on the Hemi 6. Many of his accounts are first-hand and he became head of the engine engineering department in the 1970s iirc. I'll check again when I'm home, at work currently lol.