If you read car magazines of the late ’60s and early ’70s, you can’t help but notice the tunnel vision: It’s all about straight-line acceleration over distances up to a quarter mile at a time, and never mind the handling, the ride, the brakes, or the gas mileage. Rowing against the tide, Olds tried to emphasize all those qualities with the rare L66 Turnpike Cruising Option for the 1967 Oldsmobile Cutlass Supreme, an outstanding all-around car and perhaps the best road trip vehicle among late ’60s domestic models.
The Oldsmobile L66 Turnpike Cruising Option, which Paul has previously covered at CC, was a rare example of a late ’60s engine option specially tailored not for power and performance, but for fuel economy. Its engine was an economy-oriented adaptation of the slightly oversquare 400 cu. in. V-8 used in the 1965–1967 4-4-2, matched with a 2.56 axle ratio.
Two-barrel economy engines were nothing new — by 1967, you could even get one in the Pontiac GTO — but the Oldsmobile L66 engine was unusually elaborate. It retained the 10.5 to 1 compression from the 4-4-2 engine, but borrowed the two-barrel Rochester 2GC carburetor from the Rocket 330 engine in the base F-85 and Cutlass, with a special camshaft (using the same valve timing as the 330-2V, but with more valve lift) and a special thermostatically controlled “Climatic Combustion Control” system that maintained a near-constant carburetor intake temperature, allowing the carburetor to be set leaner. Press cars also had breakerless capacitive discharge ignition for more consistent spark performance, although this was a separate option.
With such cool valve timing (intake duration was only 250 degrees), the L66 had no real top end, but it also didn’t really need any: It was optimized for wide throttle openings at lower engine speeds, delivering a big swell of torque while minimizing fuel consumption. Acceleration was more than adequate (Car Life recorded 0 to 60 in 8.2 seconds, Motor Trend 8.7 seconds), and the engine could return 19 mpg in legal freeway cruising. Flat out on a German Autobahn, it would have eventually become objectionably breathless, but the L66 was well-suited for American driving conditions.
Better still, the L66 required the three-speed Turbo Hydra-Matic rather than the two-speed Jetaway Oldsmobile offered with the 330. The Turnpike Cruising Option also included the heavy-duty chassis equipment from the 4-4-2, with firmer springs and shocks and front and rear anti-roll bars, albeit with 7.75-14 whitewalls rather than the F70-14 redline tires specified with the 4-4-2.
The L66 package was also available with UniRoyal Max radial tires (in 195R14 size), although they were rarely specified and their tread compound, selected for low rolling resistance, didn’t do grip any favors. As with the 4-4-2, the L66 package did nothing for the A-body’s inadequate brakes, but power front discs were optional for $104.79.
How did the Turnpike Cruising Cutlass fit into the general scheme of late ’60s cars? Smaller compacts like the Falcon or Rambler Rogue could equal or exceed its mileage, but not its performance. Low-price full-size cars with base V-8s had more space and were only a little thirstier, but were much slower and not as plush as a Cutlass Supreme. Rival intermediates, even without Supercar engines, could potentially beat the L66 in straight-line performance, but couldn’t match its handling and used a lot more fuel.
Supercar fanciers generally didn’t care much about handling or gas mileage, and quiet highway cruising was much less important than performance on the drag strip or in stoplight grudge matches. For almost everyone else, the Turnpike Cruising Option made a lot of sense. I’ve never been sure why Oldsmobile didn’t offer it on the four-door Cutlass Supreme or the Vista-Cruiser, since the package made for a great road trip car.
I’d rather have a Cutlass Supreme Holiday Coupe, but this L66 Cutlass Supreme convertible has a lot to recommend it. If you wanted to take a day trip up the Pacific Coast Highway with the top down, the heavy-duty suspension gave you greater composure for the twisty bits with little sacrifice in overall comfort. There was ample passing power, aided by the switch-pitch TH400 transmission, and the L66 engine’s superior gas mileage meant much better range. With the L66, the 20-gallon fuel tank was good for over 300 miles on the highway, where even a cautious 4-4-2 driver needed to start looking for gas stations by about 200 miles.
Given a choice, I think I’d prefer a blue interior like the one in the hardtop shown below to the white vinyl of this convertible, but at least it’s not black, reducing the “sitting directly on the griddle” feeling of black vinyl in an open car. It also has air conditioning, tinted glass, and a power decklid release, although unfortunately not front discs, which I’d consider a must for these cars.
I’d also have paid the $84.26 for the U21 Rocket Rally Pac: Its tachometer and tiny clock were basically useless, but having actual gauges for coolant temperature, oil pressure, and amperage seems worthwhile.
The list price of the Turnpike Cruising Option didn’t include the $236.97 price of the required Turbo Hydra-Matic transmission, but the THM was desirable anyway, and it was only $31.60 more than the two-speed Jetaway in the regular Cutlass Supreme. The L66 package was an extra $142.18, which included whitewalls ($31.60 separately) and the K50 Climatic Combustion Control system ($33.70 on other Cutlass Supreme engines), so you were paying $76.88 for the 4-4-2 chassis and the special engine. For comparison, the 4-4-2 package listed for $184.31. The capacitive discharge ignition system was $100.05 with either 400 engine, which seems pricey relative to its admitted benefits.
That was unfortunately the market’s reaction to the L66 option, which sold poorly. Contrary to popular belief, gasoline wasn’t dirt cheap on an inflation-adjusted basis, but paying more to save on gas didn’t yet compute for a lot of American buyers. Also, it took a technically savvy customer to recognize why the 300 hp L66 engine might be worth more than the 320 hp 330-4V that was standard in the Cutlass Supreme, and technically savvy buyers at that time were probably more interested in the W30 Force-Air Induction system.
To me, though, a properly equipped 1967 Cutlass Supreme L66 is the most desirable iteration of the most attractive version of the Cutlass line, and one of the best all-around cars of its time.
Related Reading
Automotive History: The 20 MPG 400 Cubic Inch 1967 Olds Cutlass Turnpike Cruiser (by Paul N)
Vintage Motor Trend Comparison: 1967 Oldsmobile Cutlass Turnpike Cruiser And 4-4-2 — Performance And Economy (by Rich Baron)
CCCCC Part 3 (1966 -1967): 1967 Oldsmobile Cutlass Supreme – America’s Love Supreme Starts Here (by Paul N)
Car Show Outtake: 1967 Olds Cutlass Convertible With A Six And Three Speed Column Shift (by Paul N)
Very Nice-looking car. I agree that the Holiday Coupe might even be better looking than the Convertible.
I think the car’s biggest problem in finding buyers was the need for premium gas. Skinflints who were looking to maximize gas mileage didn’t want to pay for premium fuel, and those who didn’t mind paying for premium were more interested in performance. This car didn’t really satisfy either group. I suspect that a premium gas 400 4 bbl with a THM and the right axle ratio could have probably gotten within a couple of MPGs of this car, at least on the highway. But these specs sure looks good to me in 2025.
The point of not using a four-barrel was to keep the intake velocities high at low to medium rpm, to complement the unusual cam profile. It wasn’t just about the tall axle ratio, which you could get elsewhere: It was set up so that you would keep your foot in it (wide throttle openings for reduced pumping losses) and engine speed low (for reduced frictional losses). Since the valve profile and gearing made engine speeds much over 3,500 rpm unlikely, more carburetion would have hurt more than it helped.
Interesting. I wonder how the Quadrajet stacked up against the 2bbl during the development phase.
I think that 2 barrel always is “throttled” compared 4 bbl.
I think there should be also intake manifold with smaller diameter for higher mkxture velocity (and then better mixture movement in cylinder).
2 barrel may be better in keeping A/F mixture ratio in these driving scenario but not minimising throttle loses.
Here EFI really was gamechanger.
How was the L66 option actually advertised and marketed–or was it? It would have been interesting to apply the same concept to a smaller, lighter car with a smaller engine.
I don’t think it got much of a push. Oldsmobile did advertise the Climatic Combustion Control system (which was also available as a standalone option), but the L66 package gets only a brief mention even in the brochure: “Special Turnpike Cruising Package also available on 2-door models to provide top economy at highway speeds.”
Very interesting article!
I wonder if the lack of success is due to the fact that people who value thrifty engines might not be looking at an Olds in the first place, and the necessity of premium fuel cannot have helped.
Still, the Turnpike Cruiser seems like a very balanced car
Pontiac was also pretty big into this basic concept of large 2V V8s and very high axle ratios, even as standard equipment. It allowed the standard engine 389 V8 Catalina to be quite competitive with a 283 Impala in terms of fuel economy. And these were regular fuel engines.
I’m not surprised this L66 package didn’t sell, it was just too outside the bounds of what typical buyers were looking for. It might have worked better as a complete trim package and name, along the lines of the Cutlass Salon ten years later. But then that wasn’t exactly a hot seller either.
My 1967 Galaxie was similar, with a 2 bbl 290 mated to a tall axle. But Ford also detuned the 2 bbl a bit to use regular gas. The drop was 45 gross hp, from 315 on the premium gas 4 bbl to 270.
The premium gas requirement would certainly seem to be a detriment for the L66. I can easily see more than a few prospective, highway-oriented buyers saving the dough and going with the more mundane 330 with its regular fuel, 9.0:1 compression ratio (even in 4v guise and the two-speed Jetaway transmission). For something intended as a freeway cruiser, the 330-4v, regular fuel V8 would seem to be adequate for most.
There’s a comment somewhere that the Olds engineers preferred the L66 400-2v as their personal rides, i.e., “an engine designed by engineers for engineers”, says it all. Not to mention that they very likely weren’t footing the bill for the cars.
1. The disc brakes shown in the article are the newer, single-piston Delco calipers, not the ’67–’68-spec four-piston calipers. Someone did a “disc brake conversion” using the more-popular and less-expensive ’69–’72 A-body parts.
2. I believe the 2-barrel carb was a compromise for fiscal economy, not fuel economy. “…optimized for wide throttle openings at lower engine speeds…” A Rochester two-barrel of that era, throttles opened far enough to “reduce pumping losses” is also going to be using it’s power-enrichment system (“power valve”.) Perhaps the power valve spring was soft enough to keep the power valve shut until the throttle blades were nearly WFO.
A buddy of mine had a maroon ’67 Cutlass Supreme, well-used, a “high-school hot rod” with the wrong JCWhitney camshaft for the 330’s lifter bank angle, and–supposedly–a “sprung frame” according to his father. Looking at the photos in this article brought back memories. Thanks for that.