and a gold-accented grille were added to distinguish Roadmaster. Horsepower was increased to 236, and a new variable-pitch Dynaflow, in which the stator blades changed pitch under hard acceleration, provided quicker off-the-line getaway. Back-up lights were now standard. Overall sales were 64,527 (which was 8% of the model year production). and the Roadmaster Convertible replaced the exclusive Roadmaster Skylark convertible. In 1956 Roadmaster had a shallower Sweepspear that did not dip down to the rocker panel as on other models. Twin chrome strips were on the decklid with Roadmaster spelled out between them. Roadmaster script was positioned on the doors beneath the vent windows. Fender tip dual bombsights were standard. Two stator wheels were adopted as an improvement to Dynaflow. A brand new 4-door Riviera hardtop, proved to be the most popular Roadmaster, with 24,770 units sold and beating the pillared sedan by more than two-to-one. Overall sales were 53,427 (which was 9% of model year production). A padded dash became standard. 1957–1958 A lower body graced the 1957 Roadmaster with an even more panoramic windshield equipped with reverse slanted pillars. A red-filled Sweepspear lined the bodysides and a chromed rear fender lower panel filled the area between the wheelhouse and the bumper end, continuing to offer "Dagmar bumpers" at the front. A new centered fuel filler was located in the rear bumper, the ends of which the single or optional dual exhaust passed through. Roadmaster script was placed within the deck and grille emblems. Two-door models had a trio of chevrons on the rear quarters while the four-door models had a Roadmaster emblem nestled within the Sweepspear dip. Interiors featured a padded dashboard and were broadcloth and nylon in 4-doors, nylon in 2-doors, and leather in convertibles. Front hip room was 65.3-in. A new 364-cubic-inch engine was rated at 300 horsepower. A new ball-joint suspension system improved handling. The 4-door Riviera hardtop proved popular the previous year so that the pillared sedan was dropped from the model lineup. Also, new was a mid-year production (March 1957) Roadmaster designated as Model 75 that featured standard power seats and windows, carpeted lower doors, a one-piece rear window (instead of a three-piece that was a design feature of the smaller Special and Century models), Deluxe hubcaps, and a Series 75 script identification on the rear quarter body panel of the Roadmaster coupes and the rear door panels on the Roadmaster 4-doors, thus