1971 was the most heavily restyled year for the E-body Barracuda program — quad headlights replacing the dual round set, a new horizontal grille, the famous gill side-marker inserts on the front fenders (4 'gills' on a 'Cuda, optional). The body shell remained Herlitz's 1970 design but the front and rear bumpers, taillamps, and grille were all new.
Engine availability narrowed: 198 / 225 Slant Six and 318 still standard; 340 four-barrel as the small-block performance pick; 383 Magnum; 440 four-barrel; V-code 440 Six-Barrel; R-code 426 Hemi. After 1971 the 440 Six-Barrel and the Hemi were both gone — 1971 'Cudas with either of those engines are the muscle-era apex on the Plymouth side.
Production: significantly down from 1970 across the board, reflecting the broader collapse of the muscle market under insurance / emissions / safety pressure. Hemi 'Cuda hardtop 1971 = 108 cars; Hemi 'Cuda convertible = 7 cars. Govier's tables remain the registry-attested baseline.