1971 was the last year for the Challenger R/T trim level — for 1972 the Challenger continued but the R/T badge was dropped along with the Hemi and the 440 Six-Pack. The 1971 R/T carried a restyled split grille (twin chrome bezels) distinct from the 1970's full-width version, and revised taillamps with a more detailed lens pattern.
Engine availability: 383 Magnum standard, 340 Six-Barrel rare, 440 Magnum common, 440 Six-Pack scarce, 426 Hemi very scarce. Hemi Challenger 1971 production: 71 hardtops + 7 R/T convertibles. The 440 Six-Pack number runs to several hundred. The 340 Six-Barrel was technically the J-code engine carried over from the 1970 T/A Challenger but without the homologation overlay — meaning a 1971 J-engine Challenger is a sporadic factory variant rather than a packaged car.
Production was roughly half of 1970's R/T volume across all engines, reflecting the same muscle-market collapse that hit the 'Cuda. Real 1971 R/Ts are identifiable by JS prefix in the body code (JS23 hardtop, JS27 convertible, JS29 hardtop with SE luxury layered on).