They made 16,437 Challengers, no breakdown on Rallye vs non-Rallye. They made 6,745 1974 Barracudas and 4,989 Cuda's in 1974. So, the 1974 Cuda's, and even the Barracudas are much rarer than the Challengers. this seems to be the case with most other years as well, Dodge just did a better sales job than Plymouth
*I don't think they had Cat's on any year, just mufflers and resonators.