Wail in the Night: The Poor Man’s Corvette?

by Steve Magnante. Photos by David Freers. Source: Motor Trend, January 2013

Imagine yourself as the general manager of Chevrolet in 1966. You’re at the wheel of the largest division of General Motors, with total passenger car￼ production in excess of 2 million units under your watch. Things are good, right? Not so fast. In 1966, Chevrolet was taking a beating on several fronts, and there was a sense that the competition was beginning to eat USA-1’s lunch. The greatest hit came from Ford’s Mustang. Without any direct competing model to consider (the Camaro was still a year away), a million Mustang buyers skipped past Chevy showrooms, where boxy Chevy II Novas and reputation-tarnished Corvairs were the only lines of defense. In this context of mounting hostility from Ford and the rest of Detroit, the last thing Chevy wanted was more competition from within General Motors. And that seems to be where the story of the Pontiac XP-833 begins—and ends.

The sleek silver two-seat Banshee sports car on display was poised to enter production in 1966, but obviously never reached that goal. Some say its demise was a direct result of complaints from Chevrolet that it would bite deeply into Corvette sales. That assumption makes sense in light of the fact the XP-833 was a fiberglass-bodied two-seater, just like the Corvette. And with annual Corvette sales in the low 20,000-unit range, there wasn’t much room for competition. But this assumption ignores the fact that, in the early 1960s, Ford also seemed poised to reenter the two-seat sporty car market previously occupied by the 1955-1957 Thunderbird. This intention was hinted at with the October 1962 introduction of the Mustang I concept, a mid-engine two-seat roadster powered by a small V-4. Also worthy of note is the 1960 Chrysler XNR. Flamboyantly styled by Virgil Exner, this two-seater sported unique asymmetrical body and trim features capped by a wild dorsal fin. The XNR added fuel to the speculation that the other two-thirds of the Big Three were looking very closely at the two-seat sporty car market. And let’s not forget privateer Carroll Shelby’s legendary pairing of goods from AC Cars of Britain and FoMoCo as early as 1962.

In light of these highly publicized goings-on, the XNR was displayed at the 1960 New York auto show; the Mustang I was officially unveiled at the 1962 U.S. Grand Prix at Watkins Glen; and Shelby’s Cobras were conquering road courses from coast to coast—there was plenty of speculation that the Corvette wasn’t going to be America’s only sports car for much longer. In such a climate, it’s easy to understand why Pontiac would want to snare a piece of the action. And so was born the XP-833. We spoke with Bill Collins, former staff engineer of Pontiac’s Advanced Engineering (i.e., future product) group. As a close associate of Pontiac Motor Division head John DeLorean since Collins’ arrival there in 1958, Collins said, “Someday, you’ve got to let us do a two-passenger sports car,” to which DeLorean replied, “Someday, we’ll do it.” That day came in late 1963, when DeLorean approved funding for design and construction of the XP-833 two-seat sports car program. According to Collins, the body design was strongly influenced by the rear-engine Corvair Monza GT show car of 1963, and not Larry Shinoda’s 1965 Mako Shark II Corvette show car, which morphed into the 1968 production Corvette. Collins adds, “We were working up exterior styling with Ned Nichols’ design studio, and the Monza GT was our primary inspiration.” ￼ Collins and his team set about their work in the fully equipped Pontiac engineering building. One of his previous assignments was to lead development of the novel flexible steel driveshaft and rear-mounted transaxle that appeared beneath 1961-1963 Pontiac Tempest production models. The Tempest was Pontiac’s first compact car, and moving the weight of the transaxle to the rear end of the body resulted in nearly ideal front/rear weight distribution. So it might be assumed the XP-833 would also utilize the transaxle drivetrain and perhaps even be based on a shrunken 1963 Tempest unibody platform. This was not to be. In reality, the swing-axle Tempest models were only marginally successful in the marketplace. The buying public never grew to appreciate the extra engineering details under its metal skin. So, for the 1964 model year, the Tempest was entirely redesigned as a more conventional body-on-frame offering with larger dimensions and a live rear axle. It also became available with the optional GTO package, and a legend was born. But we digress.

With the swing axle bits no longer in production, Collins’ team took a few sections from the conventional 1964 Tempest perimeter frame and Salisbury-style 10-bolt live rear axle as jumping-off points for their small fleet of handbuilt concept cars. To get a better idea of what they hatched, we put the XP-833 coupe up on a lift at the Milford, Connecticut, shop of its current owner, Len Napoli. Let’s explore the chassis and suspension from front to rear. Collins tells us the production version was intended to be of unitized steel construction with a bonded fiberglass skin. The XP-833 rides on a hybrid￼ frame featuring a conventionally implemented steel perimeter frame, but with no distinct body bolt-down attachment points. Rather, the floors of the body shell are of simple flat steel sheeting and are permanently welded to the box frame. Numerous raw welded seams are visible, and everything is protected by a heavy coat of black paint.

The production version no doubt would have featured much larger formed frame and floor sections with spot welds keeping it all together, rather than the puzzle of flat sheet steel beneath this handbuilt concept. The coil-spring double A-arm front suspension uses what appear to be normal stamped steel A-arms, but they’re not from the anticipated 1964 Tempest parts bin. Further research also excludes the 1961-’63 Tempest or Corvair parts bins (the first-generation Tempest shared many items with the Corvair). It seems unlikely GM would tool up specific stamped control arms just for these handbuilt sportsters, so we’re at a loss as to their origin. We do know a pair of small-diameter coil-over shock/spring units support the lightweight nose without strain and a conventional idler/pitman-arm steering arrangement with a manual box directs the tires￼. No rack and pinion here. The rear suspension is much more of a work in progress. Though Collins’ group likely cast an eye toward the Corvette’s then-revolutionary independent rear suspension, XP-833 uses a standard Tempest 10-bolt live rear axle, but that’s where the parts-bin sourcing ends. The four-link setup with a full Watts linkage is entirely made up of hand-welded steel plate and tubing.

Of particular interest are the numerous holes bored into each of the four suspension links at carefully measured positions. Collins explains the holes allow for subtle length-adjustment for suspension geometry evaluation—a through bolt locks the setting. We asked Collins how much real-world track testing was done on the cars, and he replied, “We took them out to the Milford proving grounds and drove them. They were development cars and we used them hard, especially on the ride and handling course to develop the live axle rear suspension and its final geometry.” The adjustable, handmade rear links offer moot testimony that work was not finalized when the program ended. In production, these links would have been conventional steel stampings. Coil springs and conventional shock absorbers support the back end, and help keep weight down versus leaf springs. Collins notes that ground clearance wasn’t an issue despite the low silhouette. That’s helped in part by the positioning of a single muffler inside the extra-wide transmission tunnel. It traps the driveshaft and is very similar to the way every 1984-1996 C4 Corvette tucks its catalytic converter in a similar void for the same reason. Final undercar details are a conventional aluminum case T-10 four-speed manual, cast aluminum clutch housing, and standard 9.5-inch manual drum brakes at each corner. ￼ If you’re getting the feeling the XP-833 rides on a very cost-conscious chassis, you’re right. Collins tells us, “The objective was to use some of the basic A-car chassis components, so you don’t have to retool them. The silver coupe demonstrates what would have been the base model, the price leader.” Backing this up is what we find under the hood: a straight six! While Corvettes hadn’t used a six since 1954, Collins chose Pontiac’s new-for-1966 230-cubic-inch overhead-cam six with its pioneering flex-belt-driven cam drive￼. But rather than the sexy 215-hp Sprint version with its Rochester four-barrel carburetor and two-piece cast iron header, this one’s the basic model with a pedestrian one-barrel carburetor, log-style exhaust manifold, and 165-hp rating. Collins tells us the idea behind the XP-833 was to deliver an affordable and fun two-seat sports car, not an exotic road racer. But, he adds, “There was going to be a long option list,” so few production examples would have been as austere as our silver coupe. In fact, a second XP-833 was constructed with a 326 V-8 just to give a taste of what was possible with extra power. This car exists today in Joe Bortz’s collection and is a roadster (actually a coupe minus its removable fastback top).

We asked Collins if any thought was given to making Pontiac’s top 1966 engine offering, the 421, available as an option. He replied, “You’re talking to the guy who did the original GTO…what do you think? But we didn’t want to scare the corporation off initially by showing off too much. We’d have worked our way up to the big engines after the start of production.” ￼ Should the Corvette team have been frightened by Pontiac’s proposed lower-cost sports car? The likely answer is yes. While it would have snared a good number of potential Mustang buyers, its similar theme would have also been attractive to the lower end of the Corvette buyer demographic. Adding the XP-833 to Pontiac showrooms nationwide, especially at the height of GTO mania, would have resulted in excitement you could have seen from outer space. And with the possibility of options like disc brakes, performance-suspension goodies, and that big 421 riding the XP-833’s miniscule 91-inch wheelbase, maybe the 427 Corvette (half a foot longer) wouldn’t have seemed so hot after all.

And so it was when DeLorean, Collins, and the rest of the team unveiled the XP-833 to top GM executives in mid-1965. Permission and funding for further development were denied; the XP-833 program was over. Collins tells us, “From a design and engineering standpoint, the car was about 80-percent ready for production. But when the corporation said no, it instantly went to zero. We attempted to turn things around for a few weeks, but ultimately [GM Chairman] James Roche pulled the plug.” So did Chevrolet’s fear of hijacked Corvette sales really kill the XP-833 program? Collins admits, “It’s not for me to say. I wasn’t privy to those discussions. But it is fair to assume Chevrolet was not happy to see the car.” Before we throw too many rocks at Duntov’s ghost, let’s remember that none of the competing two-seat sports cars got very far at all. Chrysler’s XNR died when Virgil Exner left in 1962; the Mustang I ballooned into the sporty-but-not-a-sports-car Mustang; and Shelby sold a paltry 1,002 Cobras in its five-year production run (654 small blocks, 348 big blocks). Maybe the sports car hysteria of the early ’60s was overblown. Perhaps this 1962 quote from Ford’s Mustang I concept car press kit sums it up best: “Sports cars are by their nature controversial. They arouse the interest of the adolescent—and of those reaching second childhood; they excite the otherwise calm and accentuate the egotistical; they are admired by many and purchased by comparatively few.” The GM bean counters likely reached this same conclusion and reacted.

Fortunately, after the lethal decision, Collins and his cohort, Pontiac master mechanic Bill Killen, had enough clout to quietly place the two concept cars into on-site storage with no need for permission. In most instances, the next stop for canceled concept cars is the crusher. Manufacturers are always wary of product-liability suits when partially formed preproduction vehicles reach private hands. Not this time. The cars rested at Pontiac engineering until fall 1973. Having overseen the much acclaimed 1977 B/C full-size platform downsizing program by early 1974 (remember, most cars are designed a few years before they arrive in the showroom), Collins left Pontiac to assist DeLorean in designing the stainless-steel gullwing DMC-12. Before departing, Collins and Killen asked to purchase the pair of Banshees. “We approached the purchasing department at Pontiac and said we wanted to buy them.” With surprisingly little fuss, ownership changed, with Killen taking our silver feature car and Collins the 326 V-8-powered roadster.

At this time, Collins tells us, “There were some left-over metal Banshee script emblems from the aborted 1966 XP-798 project, a four-seat Mustang fighter with four-wheel independent suspension and a 421 Tri-Power engine. In the end, that car was never shown to the public, and the less sophisticated [Camaro-based] Firebird F-body went into production. I found the emblems at design staff and thought they’d look good on the XP-833, so I installed them on both cars in 1973.” Bill Collins is happily retired in Michigan these days. He sold his white V-8 Banshee roadster several years ago, but recently came close to buying yet another Pontiac two-seat sports car. He says, “I thought the Solstice was a great idea. It’s too bad the chief engineer on it didn’t give me enough kneeroom, or I would have bought one.”

Not lost on Bill is how the Solstice is a direct spiritual descendant of the XP-833 project. What’s more, he’s pleased that elements of the XP-833 exterior styling also influenced the 1968 Opel GT (hood blister and retractable headlamp shapes), ovoid tail panel (1970 Firebird), and horizontal-slit taillamps (1967 Firebird). The Banshee offers a rare glimpse of what might have been. And if any comparison to the nearly 66,000 Solstices sold between 2006 and 2009 can be made, perhaps Pontiac’s concept of an affordable two-seat sports car wasn’t off base after all. This article originally appeared in the Spring 2012 issue of Motor Trend Classic.

The Banshee name (a DeLorean favorite borrowed from the military fighter jet) might have applied to a range of two- and four-seat two-doors wearing coupe, convertible, and even wagon bodywork had every related XP program come to fruition. In March 1963, the XP-798 four-seat GT coupe program was launched, with convertible and wagon-back variants illustrated. The coupe was developed into a glitzy concept car, initially badged Scorpion, then renamed Banshee right before it was to take center stage on Pontiac’s 1966 New York auto show display. It featured side doors 20 inches longer than conventional coupe doors. They opened on elaborate trapezoidal hinges that articulated the doors outboard and forward. Hatches opened from the roof, gullwing-style, to facilitate entry and egress of bouffant hairdos. The car was shipped to New York, and a press release readied for April 8, but the Banshee was pulled at the 11th hour. Photos dated as late as March 1970 show the car still kicking around various GM Design studios. XP-851 was a simpler stretched version of our Banshee, with identical nose and tail treatments. An epilogue: A September 10, 1965, memo to GM Design chief Bill Mitchell orders the XP-833 exterior clay and interior bucks to be repurposed “reflecting a Chevrolet design for the two-passenger version coupe.” What else could that possibly have been but the C3 Corvette? —Frank Marku

Specifications

Engine 230-cu-in/3769cc OHV V-8, 1×1-bbl Rochester Unijet carburetor

Power and torque (SAE gross) 165 hp @ 4700 rpm, 216 lb-ft @ 2600 rpm

Drivetrain 4-speed manual RWD Brakes front: finned drum, rear: finned drum

Suspension front: control arms, coil springs, anti-roll bar; rear: live axle, coil springs

Dimensions: L: 167.6 in, W: 67.0 in, H: 45.0 in

Weight 2,750 lb (MTC est)

Performance 0-60 mph: 9.2 sec, quarter mile: 16.7 sec @ 82 mph, 60-0 mph, 152 ft (Motor Trend January 1966, Tempest Sprint 4-speed with the 4-bbl, 207-hp engine, hence nearly equal weight-to-power)