1965-1967 Buick Gran Sport

By: the Auto Editors of Consumer Guide

This restyled 1966 Skylark Gran Sport convertible  design details. See more pictures of Buicks.
This restyled 1966 Skylark Gran Sport convertible design details. See more pictures of Buicks.

Buick in the 1960s was one of the last marques to enter the muscle car sweepstakes. But patience is a virtue, it's been said. When the "old man's car" finally did flex its muscles, it turned out that there were plenty of them to show off.

­ By "muscle car," we mean the classic conception of the type: an intermediate-class car with a powerful engine and other performance-enhancing gear. In Buick's hands, this meant the Skylark-based Gran Sport. The whole movement had been presaged a few years earlier by a spate of full-size specials with big mills and custom trim.


Buick entered this new market segment in 1962 with the Wildcat. Then came a major turning point in 1964. Pontiac snuck a big-car engine into its mid-size Tempest and created the GTO. Its popularity was nearly instantaneous and just as quickly, the "Goat" had imitators.

That same year, Oldsmobile responded with the 4-4-2, while those who favored a hot small-block engine under the hood could opt for the new Chevrolet Chevelle Malibu Super Sport or Mercury Comet Cyclone.

Meanwhile, at the outer limits of performance, there were marginally street-legal dragstrip specials: Dodges with a new-generation "Hemi" engine and a few Fairlane Thunderbolts with Ford's 427-cid V-8. If Buick was going to jump aboard this new bandwagon, in which of these forms would its entry be?

Aside from red-lettered badges, there weren't many external clues to identify the 1965 Gran Sport.
Aside from red-lettered badges, there weren't manyexternal clues to identify the 1965 Gran Sport.

The problem for Buick was made more vexing by General Motors's insistence on a maximum of 400 cid for its A-body intermediates. "Tom Murphy was [General Motors] chairman at the time and he had a lot of ethics," said Cliff Studaker, head of Buick powertrain engineering at the time. "He didn't want to be known as a power freak, as promoting speed."

There was a 300-cid V-8 available for Buick intermediates, but it was far too tame for a muscle car. The next step up was a 401-cid engine, the 325-bhp "Wildcat 445" V-8, but, according to the edict, that was too big.

Just 2,147 convertibles got the 1965 Buick Gran Sport option package.
Just 2,147 convertibles got the 1965 Buick GranSport option package.

Buick answered the problem elegantly; the division renamed the 401 a 400, stuffed it into an A-body Skylark, and created the Buick Gran Sport, which arrived as an option package part way through the 1965 model year.

"When design on the Gran Sport was under way, we knew we had a 400-cubic-inch engine in design, but it never would have been ready by 1965," said Nelson Kunz, who worked in Buick engine development for 46 years. "Pontiac had a [389] for their car, but the corporate rule said not more than 400. When Pontiac found out we were putting in a 401, they complained to management. The bosses said, 'This is ridiculous. Let's quit talking about it.' It was closer to 401 than 400, but it was under 401."

For more on the Buick Gran Sport engine, continue on to the next page.

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1965 Buick Gran Sport Design

The sales leader of the 1955 Buick Gran Sport was the two-door hardtop, with more than 11,000 orders.
The sales leader of the 1955 Buick Gran Sport wasthe two-door hardtop, with more than 11,000 orders.

Stuffing the big V-8 engine into the Skylark was a challenge in the 1965 Buick Gran Sport design for a number of reasons. According to Dennis Manner, who was in charge of Buick engines at the time, "We had to make changes." Specifically, the exhaust manifold had to be rerouted around the Skylark's frame.

"The spacing under the hood was cramped because of the width of the engine," Manner added. "We made the manifold longer and gave it a different configuration. There was special shielding for the starter because of the heat, and the accessory drive with the options was changed. The throttle linkage was specific to the vehicle and there was a specific air cleaner."


In the Gran Sport, the Wildcat engine had a single four-barrel Carter AFB carburetor and 10.25:1 compression ratio. A dealer-installed dual four-barrel setup was available. With it, horsepower rose to 338 and torque also went up to a whopping 465 pound-feet.

The Gran Sport engine also used a different oil sump and pan. "Buick had different sumps and pans because of the different chassis they produced," said Manner. "There was no significant power change" with the modifications, he added. "There was a bigger problem keeping the rear wheels on the pavement." After all, the standard engine in the 1965 Skylark was a 225-cid V-6 that pumped out a sedate 155 horses. The Wildcat V-8 offered more than double that power rating.

The 1965 Gran Sport could be dressed up with accessories like a vinyl top and wire wheel covers.
The 1965 Gran Sport could be dressed up withaccessories like a vinyl top and wire wheel covers.

Called the "nailhead" by hot rodders because of its relatively small valves, the Wildcat 445 V-8 was descended from the division's first ohv V-8 of 1953. It was a good engine for Buick. It was relatively light and offered lots of torque -- 445 pound-feet, which is where the numerical part of its name came from. What the Gran Sport engine ceded to the GTO powerplant in terms of horsepower it made up for in torque.

"The exhaust valve was smaller than normal for that engine," added Kunz. "It was too small. But we kept it open longer. We used overlap with the cam. If a valve's a little small, you just start [opening it] a little early and hold it open longer. The inlet valve was closer to normal size."

"Buick cars were typically heavy because of their high option content," said Manner. "We concentrated more on torque than horsepower because of the heavy weight. It didn't help with NASCAR, but on roads and freeway ramps it was great. Torque is what moves the car. It had a lot of torque for a relatively light engine."

For more on the 1965 Buick Gran Sport, continue on to the next page.

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1965 Buick Gran Sport

The 1965 Buick Gran Sport's lineup was completed by a fixed-pillar coupe.
The 1965 Buick Gran Sport's lineup was completedby a fixed-pillar coupe.

Putting the 1965 Buick Gran Sport's power to the road was the standard mix of transmissions available at the time: three- and four-speed manuals, and a "Super Turbine Drive" two-speed automatic.

Out of 15,780 Gran Sports produced the first year, the three-speed was, understandably, the least popular with only 1,132 made. The four-speed was second in popularity with 4,289, while the automatic was the surprising overwhelming favorite with 10,359 ordered.


The only concession to the extra power was that the Gran Sports were built on the convertible's sturdier frame. The suspension was also modified with a fatter antiroll bar in front and a control arm suspension in the rear to limit axle hop and side-to-side movement. Finishing up the package were special bushings, springs, brakes, and wheels.

Straight-line performance was the goal, though, and the Skylark Gran Sport offered that in spades. A Gran Sport driven by a capable driver could attain 60 mph from a standing start in 6.8 seconds and cover the quarter mile in 14.9 seconds at a top speed of 95 mph. Even with the automatic, 0-60 times were in the mid-seven-second range. Car Life took 7.4 seconds in the 0-60 run, while Motor Trend took 7.8 seconds.

"In typical Buick fashion," wrote Marty Schorr in GNX Buick, "the Skylark GS was more conservative in appearance than the GTO and did not benefit from extensive performance and dress-up option lists. However, the Skylark offered comparable handling and performance qualities which the GTO owners discovered, much to their dismay."

This 1965 Buick Gran Sport coupe's four-speed transmission was an added-cost option.
This 1965 Buick Gran Sport coupe's four-speedtransmission was an added-cost option.

Badging helped distinguish the Gran Sport from other Skylarks. Red "Gran Sport" badges adorned the rear deck and grille, as well as the roof sail panels of two-door hardtops and fixed-post "thin-pillar" coupes, or the rear fenders of convertibles. There was even a "Gran Sport" badge on the dash.

The Skylark Gran Sport package, which cost around $250, also had bucket seats (a $70 "mandatory option") for its driver and front passenger, and a bench in the rear. The shifter was on the floor, no matter which transmission was installed. Among the options were a tachometer, air conditioning, and 14-inch versions of Buick's five-vane "Wildcat" sports wheels. In that less safety-conscious era, the seat belts could be deleted for credit.

Buick advertised the Skylark Gran Sport as "A Howitzer With Windshield Wipers." One ad read "You don't tuck a Wildcat V-8 into just any cage."

Another said "Some people might think a whacking big 400-cubic inch, 325-hp Wildcat V-8 alone is worth the price of admission to a Skylark Gran Sport. Not us Buick People. We had to go and lock that engine to a heavy-duty suspension, a floor-shift 3-speed that's synchronized in all forward gears, and the kind of steering and handling that'll make you want to leave home at the first hint of an open road."

The hardtop garnered the most orders with 11,351 produced. The coupe was next with a mere 2,282 produced, followed by the convertible with 2,147 produced.

To follow the changes introduced for the 1966 Buick Gran Sport, continue on to the next page.

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1966 Buick Gran Sport

Like its corporate siblings, the 1966 Buick Skylark Gran Sport was new all over.
Like its corporate siblings, the 1966 Buick SkylarkGran Sport was new all over.

The next year proved to be a transition year for the 1966 Buick Gran Sport. The biggest changes came in styling. The 1966 Gran Sport looked more like a performance car after Buick designers had a chance to fiddle with the product.

For one thing, the hood ornament was gone because muscle cars didn't have hood ornaments. But muscle cars did have hood scoops; the Gran Sport got a pair, albeit fake. There was a blacked-out grille, and the full-width taillights of 1965 were replaced by a black-matte finish rear cove panel and rectangular outboard taillamps.


The straight-through fender line was replaced for 1966 by a "kick-up" in the rear quarter panels; roofs on closed cars took on a bit of a slope and featured a backlight sunk between long sail panels. Front bucket seats were no longer mandatory -- a front bench seat with a folding center armrest was standard.

The new body made the 1966 Buick Gran Sport look a bit like a baby Wildcat.
The new body made the 1966 Buick Gran Sport looka bit like a baby Wildcat.

On the other hand, chassis and suspension construction were essentially the same. Tires continued at 7.75 × 14, but now in a choice of whitewall or red-line styles. The 325-bhp, 401-cid Wildcat V-8 was continued, but an optional 340-horse single four-barrel version was advertised.

Base prices for the 1966 Gran Sport ranged from $2,956 to $3,167. Total production dropped to 13,816, with the hardtop again taking the lion's share of production with 9,934 examples. Buick produced 2,047 convertibles and 1,835 coupes. As in 1965, GS buyers flocked to automatic transmission-equipped cars.

Demand for the 1966 Buick Gran Sport coupe slipped below the 2,000 car mark.
Demand for the 1966 Buick Gran Sport coupeslipped below the 2,000 car mark.

Buick ended its engine charade in 1967 with a brand new 400-cid powerplant designed by Denny Manner under Cliff Studaker's direction. "We all worked together," Studaker said modestly, but he had been promoted to executive engineer in charge of all engines, so the new mill was his baby.

Actually, two new engines were built for the 1967 model year; the 400-cubic-incher and a 430. "We made the 400 specifically for the purpose of putting it in a Gran Sport," Studaker said.

The 1966 Buick Gran Sport two-door hardtop remained the volume car in the line with 9,934 sold.
The 1966 Buick Gran Sport two-door hardtopremained the volume car in the line with 9,934 sold.

According to Studaker, the 400 was an underbored 430-cid Wildcat V-8. Even with the smaller bore (4.04 inches versus 4.19), the engine was over-square "by far," he said. The 430 developed 360 bhp at 5,000 rpm and 475 pound-feet of torque at 3,200 rpm, while the 400 put out 340 bhp at 5,000 rpm and 440 pound-feet at 3,200 revs. Both used single four-barrel carburetors and a 10.25:1 compression ratio.

"When we designed the 400 to replace the 401, not a part was interchangeable," said Manner. "The distributor was in the front, not the rear. It drove the oil pump up front. The oil pump was in the rear in the 401. The cylinder firing order was different."

For more on the new engine and on the 1967 Buick Gran Sport, see the next page.

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1967 Buick Gran Sport

The dummy hood scoops were reshaped for the 1967 Buick Gran Sport.
The dummy hood scoops were reshaped forthe 1967 Buick Gran Sport.

The 1967 Buick Gran Sport engine had bigger manifold branches, larger valves, and improved exhaust headers that assured minimum gas flow restriction. Intake valves were 18 percent larger than in 1966 and the exhaust valves were 56 percent larger. There went the old "nailhead."

Other innovations included water jackets in the cylinder heads that were carried around the spark plug holes. In addition, conical spark plug seats eliminated the need for plug washers.


"There were a couple of important reasons for the change," wrote Larry Gustin and Terry Dunham in The Buick: A Complete History. "The first was breathing flexibility. The earlier engine featured vertical valves with a pent roof combustion chamber, necessitating a valve actuating mechanism in which the pushrods passed through bosses drilled in the cylinder heads crossing the valve guides with the rocker arms and doubling back to actuate the valves. Valve and port sizes were limited in this arrangement.

At $3,167 to start, the convertible was the costliest 1967 Buick Gran Sport.
At $3,167 to start, the convertible was thecostliest 1967 Buick Gran Sport.

"In the new engine there was a domed chamber (Buick engineers called it a 'slanted saucer') designed by [engineer Joseph] Turlay before his retirement, with conventional rocker arms and pushrod placement, and a 15-degree angle between valve and cylinder axes. ...

"Since the industry trend seemed to be away from the classic wedge chamber, this was a surprise as well. But the domed chamber with small quench area had a significant feature and represented the second important reason for the change. It boasted considerably less surface area in relation to displacement volume than the conventional wedge. While this did not reduce octane requirement, it did result in higher efficiency (power and fuel economy) and less emission of hydrocarbons."

But there were more changes than in the engine department alone. For one, the Gran Sport wasn't a Skylark any more. As Popular Mechanics put it, "Probably feeling the 'Skylark' tag might be too much for the birds, Buick folks 'officially divorced' what is now the GS-400 from the Skylark series. They're probably right -- a ruddy young male would much prefer a masculine GS-400 to a fine-feathered bird."

Instead of fender skirts, which were available on the Skylark, the GS had open rear wheel housings that showed off its F70 x 14 wide-oval red- or white-stripe tires. General styling was left intact, but the grille adopted a thicker horizontal bar bisected by a strong vertical spine. Taillights were enlarged a bit, too. Cars equipped with optional front disc brakes also required special wheels, hubcaps, and beauty rings.

Among the features on this 1967 GS-400 convertible are automatic transmission and full-length console.
Among the features on this 1967 GS-400 convertibleare automatic transmission and full-length console.

Gustin and Dunham added that Buick's brakes were recognized as the best in the industry (though some journalists who tested 1965 and 1966 Gran Sports were critical of their all-drum brakes), and they were made even better for 1967: "Front power discs were optional on most models, aluminum brake drums were extended to GS-400 and Sport-wagon, and on the larger cars the system-was improved through the use of a larger power booster, better linings and a doubling of the number of fins in the brake drums."

Compared to its 1965 Gran Sport test car, Car Life found that not only was a 1967 GS-400 faster to 60 mph (6.6 seconds) and in the quarter mile (14.7 seconds), but with front disc brakes, its deceleration rate from 80 mph was substantially quicker and virtually without fade.

The GS-400 also now had a junior partner. As one Buick ad put it, "Our now-famous GS-400 ... doesn't come for peanuts. It's a great car -- but just a little rich for some people. So we set to work and designed the Buick GS-340. It has a smaller engine (but it weighs a lot less). Its interior isn't quite as sumptuous (but it's clean and simple and tasteful). It has its own exterior paint: a broad rally stripe, and contrasting hood scoops. And its own ornamentation and the full complement of GM safety features. We ended up with a car that does indeed cost less than the GS-400. But one with its own brand of excitement."

Not that the GS-340 was a whole lot cheaper than the GS-400. The two-door hardtop GS-340 (the only style available) had a starting price of $2,845, only $174 less than the GS-400 hardtop and just $111 less than the GS-400 coupe.

The lower price bought a GS-340 customer a car that looked like a GS-400, even if it didn't quite have the guts. Underhood was a 260-bhp, 340-cid V-8 with a 10.25:1 compression ratio. Torque was rated at 365 pound-feet at 2,800 rpm. The engine breathed through a four-barrel carburetor. A four-speed transmission was available for an extra $184. If the buyer opted for bucket seats and an automatic transmission, a full-length console could be fitted.

Bold red accents identified the 1967 GS-340, which came only as a hardtop.
Bold red accents identified the 1967 GS-340,which came only as a hardtop.

To put the power to the road, specific front and rear shocks were offered, with special springs and a large diameter stabilizer bar. Tires were 7.75 rayon cords on 14-inch rally-style wheels.

The GS-340 was available in only two colors: white or platinum mist (silver). Both wore red rally stripes and hood scoops, as well as a red lower-deck molding.

Total GS production pushed up to 17,505, aided by 3692 of the new GS-340s. The top seller was the GS-400 hardtop with 10,659 examples produced. (On the West Coast, a California GS ornamentation package could be ordered for pillared coupes, the precursor to a pseudo-sporty car that would be sold nationally beginning in 1968.)

The most popular package was the GS-400 hardtop coupe with the automatic transmission -- 8,006 were produced. Least popular was the GS-400 convertible with a three-speed manual; only nine were made.

After these first three years of feeling its way around the muscle-car arena, Buick finally figured out what to do. In subsequent years, Stage I and Stage II versions that still hold stock dragstrip records made the GS well known to performance buffs. But no matter what the year of a Gran Sport, it always got its driver to the finish line comfortably and in style.

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