The disappearance of running boards along the side and its lack of a heavy belt line molding made the sleek car appear even lower.

A not well-received new front end, which was patterned on the Lincoln Zephyr and lacked the visual punch expected by Cadillac buyers, a modest change in trim level, and some new options appeared for Sixty Special in 1939.

First among the new options was a retractable metal panel above the front seat called a "Sunshine Turret-Top Roof", a predecessor to the type of sunroof that would not become more commonplace until the mid-1970s.

Only 1 Sixty Special Town Car was made this year and used on the auto show circuit before being purchased by film director, Cecil B. DeMille.

For 28 of the next 34 model years of its existence the Sixty Special would feature a uniquely stretched GM C-Body with noticeably greater legroom and headroom.

While the model-specific interior was luxuriously outfitted, Cadillac largely depended on trim to differentiate the exterior of Sixty Special from the shorter but similarly styled Series 62 Touring Sedan.

This was largely due to the tremendous sales success of the Series 62, whose low bodies with broad shoulder room and no running boards had been inspired by the original Sixty Special.

A clever rainbow-shaped instrument cluster which put all the gauges directly above the steering column in front of the driver was used for 1948 only, while a new curved dashboard design added to passenger roominess.

The roof-mounted decorative chrome louvers and individually framed side door glass (a Sixty Special design element since 1938) were carried over to this latest model as well.

With trim inspired by the Lockheed P-38 Lightning, the new Sixty Special featured simulated side-scoops and curious tail-fins - resembling the P-38's vertical stabilizers.

A new grille was in order for 1949 – this one wider and more substantial than the previous year; the bottom and middle horizontal members framing the bright trim surrounding the parking lights and wrapping around the front fenders.

Minimal trim changes to the Sixty Special included wider rocker panel moldings, which moved the chrome louvers higher up on the rear doors, and a revised grille and bumper.

This automated system, which automatically dimmed the high-beam headlights when a forward-facing sensor indicated oncoming traffic, would become a Cadillac option for nearly the next forty years.

Sixty Special arrived with revised trim and more power (250 hp (190 kW), to be exact) for 1955, and while the $4,342 price was lower than last year, production rose slightly to 18,300 units.

Priced at a hefty $5,539 ($60,089 in 2023 dollars [4]), the 4,761 lb (2,160 kg) (shipping weight) Sixty Special production reached an impressive 24,000 units - a sales plateau that the nameplate would never achieve again.

Engineering treats included moving the optional air conditioning unit from the trunk to a space under the hood, and a foot-operated parking brake that released when the car was put in gear.

Sparkling "studs" decorated the wide new grille, while the rubber-tipped bumper guards were moved further out towards the edges of the car – leaving a lower, wider look.

New for 1960 was a standard vinyl roof covering, and the small chrome "louvers" returned (first seen in 1942, last seen in 1956) mounted on the rear fenders, just ahead of the tail lights.

[13] For 1961, Cadillac's Sixty Special received all-new sheet metal, with a crisp, limousine-like formal roofline and a mildly shorter 129.5 in (3,290 mm) wheelbase.

Sixty Special shared its lack of body-side trim with Eldorado - appearing very clean and formal compared to standard Cadillac models.

The Sixty Special (and companion Eldorado convertible) featured almost no side trim, except for a wide rocker-sill molding which ran from the rear-edge of the front fender wheel well to the rear of the car.

The Fleetwood Brougham included a formal-looking vinyl roof covering, and luxurious appointments inside such as genuine walnut trim and, for rear seat passengers, lighted writing tables (through 1967), foot rests, and reading lamps.

The formal new roof was clearly reminiscent of Bill Mitchell's original 1938 Sixty Special, with individually framed, rounded-corner side glass (outlined by a thin chrome bead).

Also new on the vinyl top were C-pillar mounted opera lamps and a thick B-pillar, which, along with a narrow body filler panel between the front and rear side doors, heightened the car's custom limousine look.

Coupled with heavy duty cooling, 3.23 gearing, high output 80 amp large frame alternator and heavy-duty THM400 transmission, the long wheelbase was ideal to pull trailers weighing up to 7,000 lb (3,200 kg).

The 1974 model year saw the introduction of the "Air Cushion Restraint System",[24] which activated airbags hidden in the steering wheel and passenger side of the instrument panel when the car was hit from the front only.

Adding US$750, this package included a unique "pillow-style" velour seating trim as well as a more plush carpeting and a few additional features optional on the standard models.

GM subcontracted coachbuilder Hess and Eisenhardt to customize standard Fleetwoods in a newly outfitted plant in Madison Heights, Michigan: cutting standard Fleetwoods laterally behind the B-pillar; extending and reinforcing the bodywork; covering the cut line with a padded vinyl roof and a wide, ribbed molding at the rocker panel; adding longer doors; and slightly modifying and re-installing the interior.

While the Sixty Special retained genuine American walnut trim on the doors and dashboard, the highly adjustable seating became theoptional $3,550 "Ultra" package.

A 1993 Sixty Special Coupe was planned and was described in the "Advance Preview Book," a July 1982 dealership supplement offering information about the upcoming 1993 model year.