Werent the bumpers and brackets different between the 73 and 74.
Oh and the whole muscle car era ended in 71 is BS. My 73 340 Duster ran just fine back in the day and a friend had a 74 RR / GTX 440 and I dont recall any of us not considering it a muscle car. Now from 75 and on is debatable but even then some good stuff still slipped through.
77 Macho Power Wagon LWB factory 440
70 Coronet 440 N code 3 speed
