At the same time GM had different V8s for each of their brands, no interchangeability there either. That's how it was in the old days.

Also, the more expensive the car, the more powerful the engine (generally). In the Chrysler world, from top to bottom: Chrysler, DeSoto, Dodge, Plymouth. So it stands to reason that the engines got smaller as one moved down the list.

My Grandpa sold DeSotos and Plymouths. If he'd been in a ritzier neighborhood he'd have been selling Chryslers and Dodges.

R.