From what I've seen, 74's still don't get as much as 72's & 73's, don't know why, cuda or Challenger.
The slant-6 was dropped in 73 and cudas and Rallye Challengers could both be had with 318's, 340's (and 360's in 74).
A friend of mine recently sold (to a now EX friend), a nice 73 cuda 340. It WAS triple black, now has a crate 360 and is yellow. Probably could be local show-ready for another $2-3K. No rust, he drove it home 140 miles with no issues. Price was $11K.