The 1958 300D continued with few changes, though an unsuccessful Bendix fuel-injection system was offered briefly, but withdrawn and replaced with dual four-barrel carburetors. Power was up to 380 hp but sales were down to 618 hardtops and 191 convertibles. The iconic Hemi was replaced by the 413-c.i. Wedge engine on the 1959 300E, claiming the same horsepower. The grille was changed and swivel bucket seats were a new and desirable option. This year saw one of the model’s lowest sales figures, with 550 hardtops and 140 convertibles trading. The 1959 model year also marked the last use for a separate frame on the letter cars.
The 300F’s fins grew to even wilder proportions in 1960, starting at the front of the door and terminating with V-shaped taillights and a “bird-bath” faux spare on the trunk. The 413-c.i. Wedge V-8 received cross-ram induction and the highest horsepower motor made 400 ponies. Sales rebounded to 964 hardtops and 248 convertibles and at least 10 cars were fitted with the French Pont-a-Mousson 4-speed. Chrysler 300Fs were timed at a remarkable 145 mph at Daytona. The 300G of 1961 would be the last “big fin” car, and the front was heavily modified to accept angled headlights. Some 3-speed cars were built, and sales climbed again to 1,280 hardtops and 337 convertibles.