For 1957, Imperial got its platform that set it apart from Chrysler’s division. This lasted through the 1956 model year. During this time, Imperials were equally wider both in the inside and outside than other Mopars, the front and rear surface equal to 64 inches and 62 inches respectively. The exterior width had a maximum of 81.7 inches for 1961-1963 which keeps record as the widest non-limousine car in America. After Lincoln downsized in 1961, it remains with no competitor as the largest car for the remainder of its lifetime.
Unlike other Chrysler divisions that introduced unit-body style, Imperials maintained separate full perimeter frames through 1966 model year. The frames had a box cross-section with cross-members forming an ‘X’. The ‘X’ had a hole where the driveshaft passed through. Before the 1963 year, the parking brake was attached to the driveshaft and not connected to the rear drum brakes. For 1957,Imperials and Chryslers had a ‘Torsion-Aire’ suspension. The Torsion-bar suspension system was to reduce unsprung weight and shifting the car’s center of gravity downward and rearward.
The Forward Look style featured a “biplane” front bumper , complete grille and headlights.It had taller tail fins that were the trademark gunsight taillights and featured a downward tapering decklid that reached the rear bumper. The Hemi engine was enlarged to 392 cu inches and standard for 1957-58. Across the line Power seats were made standard. For the first time,a convertible was available for the Imperials. Imperials were now available in three designs; Standard Imperial Custom, mid-range Imperial Crown,and the new Imperial LeBaron on top of the line. They still offered the Custom-built Imperial Crown Limousine. Optional for 1957-1961 was “Flite Sweep Deck Lid”simulated Continental tire bulge.