Oldsmobile Delta 88 Royale Rocket 455
When Oldsmobile introduced its new 455-cubic-inch Rocket V8 for the 1968 model year, it created one of the most torque-rich engines in General Motors history. By 1970, this massive powerplant had found its way throughout the Oldsmobile lineup, and in the Delta 88 Royale, it created something unique: a full-size luxury car with legitimate muscle car performance credentials. This was not the 442, Oldsmobile's celebrated mid-size muscle machine, but rather the bigger, more comfortable alternative for buyers who wanted serious performance without sacrificing rear-seat legroom or trunk space.
The Rocket 455 in the Delta 88 Royale produced 365 gross horsepower and an astonishing 500 lb-ft of torque at a lazy 3,200 rpm. These numbers were not artificially inflated - the 455 was a genuine long-stroke torque monster with a bore of 4.126 inches and stroke of 4.250 inches, displacing 7,456cc. The Rochester Quadrajet four-barrel carburetor provided excellent throttle response and surprising fuel economy at cruise, while the Turbo Hydra-Matic 400 three-speed automatic was one of the strongest transmissions GM ever produced, perfectly matched to the engine's enormous torque output.
The Delta 88 Royale occupied a sweet spot in the Oldsmobile hierarchy - above the base Delta 88 but below the Ninety-Eight. The Royale designation brought upgraded interior trim with cloth-and-vinyl seats, woodgrain dashboard appliques, full wheel covers, and additional chrome trim. The coupe body style with its formal roofline and sweeping C-pillar was elegant and distinctive. At 5,588mm (220 inches) in overall length on a 3,099mm (122-inch) wheelbase, it was an enormous car by any standard, yet the 455 V8 propelled this two-ton machine to 60 mph in under seven seconds.
Oldsmobile's engineering heritage showed in the chassis. While not as sophisticated as a modern car, the B-body platform featured a perimeter frame, coil springs at all four corners (unusual for the era - most competitors used leaf springs at the rear), and power-assisted disc/drum brakes. The four-link rear suspension provided better handling than the leaf-spring setups used by most competitors. This was a car that could cruise at highway speed in near-silence while having the reserves of power to merge or pass with authority.
The 1970 model year represented the peak of the pre-emissions big-block era. By 1971, compression ratios were dropping across the industry in preparation for unleaded gasoline requirements, and net horsepower ratings would replace the more flattering gross figures. The 1970 Delta 88 Royale with the 455 Rocket was the last of the truly uncompromised full-size performance Oldsmobiles. While the 442 and W-30 variants get the collector attention, the Delta 88 Royale remains an undervalued alternative that delivers tremendous bang for the buck. These are enormous, comfortable, powerful automobiles that represent the pinnacle of American full-size car engineering, available at a fraction of the price of comparable muscle cars.
Full-size Oldsmobiles are undervalued compared to 442s and Cutlasses. Two-door coupe is most collectible. Check for frame rust and floor pan deterioration. The Turbo Hydra-Matic 400 is extremely durable but check for leaks. Verify correct Rocket 455 engine with casting numbers. Chrome and trim parts are harder to source than A-body parts. These cars are best appreciated as comfortable cruisers rather than drag racers.
The 455 V8 was standard on the Delta 88 Royale for 1970. Available in two-door coupe, four-door sedan, and four-door hardtop body styles. The W-30 performance package was not available on the full-size platform.