Car: Plymouth RoadRunner
What makes it special: RoadRunner was Plymouth's midsize Muscle Car offering. For 1973, the Plymouth RoadRunner was given completely new sheetmetal, with a more conventional "squared up" front-end styling. It now resembled it's 4-door Satellite counterpart, which somehow boosted sales by 40% that year.
What made it famous: No 440 cu in V8 cars with 4-speed manual were built. The 400 was the biggest engine Plymouth offered with the 4-speed, which could also be had with the 318, and 340 V8 engines. The 440 V8 was still available, but with the TorqueFlite automatic transmission. As with years before, the RoadRunner had the beloved "RoadRunner" cartoon character decals, as well as the cartoon character's famous signature "beep-beep" for the horn.
Why I would want one: Being a life-long Looney Tunes fan as well as a detriot muscle car fanatic, a RoadRunner of ANY year would be a welcome addition to my collection. ( Which currently stands at just one, but I DO have high hopes for the future... )
Fun fact: The now-defunct Mopar Enthusiast magazine released a concept rendering of a potential 2010 Road Runner, with design cues based on the 1971-72 model.
( 1973 Plymouth RoadRunner photo from motortopia.com )