For 1971, the Cougar was completely restyled. Starting to move upmarket as a near-personal luxury car, the Cougar looked bigger, but actually weighed less and had only a one-inch-longer wheelbase than its predecessors (112 vs. 111 ).
The front end now featured four exposed headlights; the disappearing headlights were gone for good. The center grille piece, or cat’s nose, was now larger and more noticeable than ever.
The rear featured a semi-fastback with a “flying buttress” sail-panel.
However, the convertible returned as did the XR-7 as well as the GT package. The Eliminator package was gone forever, but the Ram Air option remained.
The engine lineup was shuffled slightly for 1971 as well. Now only three engines were offered—the standard 240 hp (179 kW) 351 Windsor 2-barrel V8, the 285 hp (213 kW) 351 Cleveland 4-barrel V8 and the 370 hp (276 kW) 429 Super Cobra Jet 4-barrel V8. However, the end of the muscle car era, which was caused by high insurance rates and rising gas prices, would spell the end of these high power engines.
Wikipedia’s Mercury Cougar Wiki