Oldsmobile Cutlass Supreme SX 455
The Oldsmobile Cutlass Supreme SX represented a different approach to performance than the raw 442 and W-30 models. Rather than focusing on stripped-down quarter-mile performance, the SX package combined the Cutlass Supreme's luxury appointments with genuine big-block power, creating a sophisticated grand touring machine that appealed to buyers who wanted performance without sacrificing comfort and refinement.
The SX package, introduced for 1970, was available on the Cutlass Supreme coupe and featured the 455 cubic inch V8 as standard equipment. In base form, the 455 produced 320 horsepower and 460 lb-ft of torque, providing effortless acceleration and highway cruising ability. The engine's massive torque output meant the SX could merge onto freeways or pass slower traffic with authority, all while maintaining the refined character expected of an Oldsmobile.
The Cutlass Supreme platform was already one of the most popular intermediate cars in America, known for its attractive styling, quality construction, and premium appointments. The SX package built on this foundation with performance enhancements including heavy-duty suspension, dual exhaust, distinctive badging, and special wheel covers. The interior featured bucket seats, console, full carpeting, woodgrain trim, and a comprehensive instrument cluster.
What distinguished the SX from the 442 was its character. Where the 442 was a muscle car that could be optioned up with luxury items, the SX was fundamentally a luxury car that happened to have serious performance. The suspension tuning was softer, the exhaust note was more muted, and the overall personality was one of effortless power rather than raw aggression. This made the SX ideal for buyers who wanted a car they could drive comfortably every day while still having the ability to show clean heels when the opportunity arose.
The 1970-71 model years saw the SX receive the beautiful new A-body styling that many consider the high point of GM intermediate design. The sweeping body lines, formal roofline, and clean detailing created a car that looked expensive and elegant. The optional vinyl roof and opera windows available on the Supreme added to the upscale appearance.
While the SX never achieved the collector status of the 442 W-30 or GSX, it represents an important segment of the muscle car market: the luxury performance car. These were vehicles that proved American manufacturers could build cars that combined genuine performance with a level of refinement that approached European grand tourers. Today, SX Cutlass Supremes offer an attractive combination of classic styling, strong performance, and everyday usability at prices well below comparable 442 models.
The SX is less valuable than the 442 but offers similar big-block performance at lower cost. Verify SX package through trim tag. The 455 engine should have correct casting numbers. Check for typical A-body rust: floor pans, trunk, lower quarters. The Cutlass Supreme's luxury features mean more things to go wrong; check all power accessories. Interior trim is Supreme-specific and can be expensive to restore. The 1970 model with the beautiful new body is most desirable.
The SX package was available on Cutlass Supreme models for 1970-1971. Total SX production 1970: approximately 10,209. 1971: approximately 6,624. The SX came standard with the 455 4V engine. The package was discontinued after 1971 as the muscle car market declined.