as side-impact guard beams in the doors and new emission control devices. New single-piston disc brakes replaced the more complex 4-piston units offered from 1965 to 1972. Chrysler's new electronic ignition system was standard equipment on all engines, and starter motors were revised for faster engine cranking. The K-frame was modified to accommodate a new spool-type engine mount that limited engine roll to 3°. The upper ball joints were upgraded to the larger B-body units. Along with these chassis changes, the wheel bolt pattern on Darts with disc brakes was enlarged from to the pattern common to the larger B- and C-body Chrysler-built passenger cars. Darts with 4-wheel drum brakes continued with the smaller bolt pattern. The standard rear axle was still the 7¼" unit, but the heavy-duty option was now an 8¼" item rather than the previous 8¾" rear axle. Standard rear axle ratios were 2.76:1 with automatic transmission and 3.23:1 with manual, though other ratios were available. Vent wings were deleted from the Swinger but not from the 4-door sedans. A new "Quiet Car" package was available, consisting of extra sound insulation, premium exhaust hangers, and an exhaust resonator. The Demon fastback was renamed "Dart Sport" in response to poor sales. It was thought that the "Demon" name and devil-with-pitchfork logo negatively affected sales to people of faith. The high-performance model thus became Dart Sport 340, and 1973 saw styling changes to go along with the name change. The Dart Sport received the same new front end as the other Darts, and its taillights were changed to two lights per side, each with a chrome trim ring. These would remain unchanged through the 1976 model year. 1974 In 1974, the US federal bumper impact standards were expanded to cover rear bumpers as well as front ones, and as a result, the Swinger and Dart sedan's rear bumpers grew much more massive. Taillights larger than the previous year's items were set above the rear bumper, rather than within it. Shoulder and lap belts were finally combined in all Chrysler products into a retractable, inertia-sensitive, single-buckle design Chrysler called "Unibelt", replacing the difficult-to-use separate lap and shoulder belts that had been installed through 1973. The Arab oil embargo of 1973, increased sales of smaller cars in the U.S. Dodge introduced the Dart SE (special edition) in mid-1974 as a four-door sedan and two-door hardtop. The SE included velour high back