I have always been amazed that the AM-FM radio cost more ($12.40) than the 340 engine upgrade when I bought my '73 Cuda. The base engine was a 318.
E55- 340 C.I.D. Engine-8 Cylinder-4BBL - $179.00
R35- Radio-AM/FM Stereo - $191.40
If this was on the Price Is Right, I would opt to say the engine cost more.