One of the early adopters of street performance (’49 Rocket V-8 coupe), Oldsmobile kicked butt with the ’66 OLDS 4-4-2: TRI-POWER ROCKET!
When carmakers announced their 1966 models in September 1965, it was like the Musclecar/Supercar floodgates had opened. Ford had already proven that its 1964-1965 marketing mantra – “Win On Sunday, Sell On Monday” – worked. For 1966, Chrysler, Ford, and General Motors unleashed their all-time hottest models, and it was nirvana for car enthusiasts and automotive magazine editors!
One of the finalists for our Top Performance Car honors at Hi-Performance CARS magazine was the ’66 OLDS 4-4-2: TRI-POWER ROCKET! Olds’ engineers had finally come up with a big-engined midsize car to compete seriously with Pontiac’s GTO. Not long after revealing the latest 4-4-2 with four-barrel 400/350, they upped the ante with a late-arriving Tri-Carb version conservatively rated at 360 horsepower. It was Oldsmobile’s first use of three-two-barrel induction since the legendary 1957-1958 371-cube J2 Rocket V8s, rated at 300 and 312 horsepower, respectively.
We found that an L69-option Tri-Carb 4-4-2 with four-speed and 3.90 Anti-Spin gearing was quicker and faster than the 360-horsepower Tri-Power GTO we tested for March 1966 Hi-Performance Cars. GTO styling was refreshed in 1966, and it became a distinctive model series, no longer an option on the Tempest. The GTO’s best time was 100 mph in 14.50 seconds, compared with an L69 Olds’ 13.80s and approximately 105 mph.
Oldsmobile engineers worked on the L79 W-30 engine project in late 1964 and 1965, and Tri-Carb packages first surfaced on ’65 4-4-2 Mules. The Lansing Engineering facility was down the road from Demmer Tool & Die, a GM supplier. There was a lot of “information” sharing between Olds and Demmer drag racing engineers. Demmer raced a Tri-Carb 4-4-2, RECTIFIER-2, and worked closely with Oldsmobile. In 1968, Demmer built the 455-inch Hurst Olds. Unlike GTO Tri-Power with vacuum-operated linkage opening the end two Rochester 2GC carburetors, the Oldsmobile L69 Tri-Carb utilized a smoother, progressive mechanical linkage.
An Oldsmobile 4-4-2 performance brochure encouraged enthusiasts to not only buy a 4-4-2, but “Turn it on. Tinker with it. Make it dance to your tune.” “Exclusive on the 4-4-2 Tri-Carb. For peak breathing at the high end, just pull two bolts from the crossover valves on either side of the center carb, rotate the covers 90 degrees and bolt them back down.” It was not great for cold starts, but perfect for taking advantage of cooler, denser air-fuel mixture for better performance!
With a choice of Anti-Spin gearing up to 3.90 and dealer-installed 4.11 or 4.33 gears, plus close or wide-ratio Hurst-shifted four-speeds, the ’66 OLDS 4-4-2: TRI-POWER ROCKET! was a serious Supercar. Taking it up a notch, it was available with a W-30 option that didn’t change the factory power rating, but unquestionably improved quarter-mile performance. Key W-30 ingredients included a chromed Tri-Carb air cleaner with four-inch hoses ducting fresh air from front bumper openings, a high-lift, 308-degree-duration camshaft, and relocation of the battery to the trunk. The majority of W-30 engines were in base model F-85 4-4-2 Club Coupes.
For complete details on the ’66 OLDS 4-4-2: TRI-POWER ROCKET!, 4-4-2 road tests, tech data, please visit OVER-DRIVE magazine @ https://over-drive-magazine.com/2023/12/30/1966-oldsmobile-mid-size-cars-fact-sheet/