The failure of the Banshee did not mean the end of the OHC six, which finally went into production in the summer of 1965. That fall, it replaced a Chevrolet-derived 215 cu. in. (3,529 cc) pushrod six as the standard engine of the 1966 Pontiac Tempest/Le Mans.
In its initial form, the Pontiac OHC six displaced 230 cubic inches (3,769 cc), the same as the pushrod six used by the Chevrolet Chevelle/Malibu, but was rated at 165 gross horsepower (123 kW) compared to the Chevy’s 140 hp (104 kW). The OHC engine was not enough to make the Tempest a fast car, but it was a bit quicker than most contemporary American sixes.
The automotive press had known the OHC six was in the works for more than a year, but its arrival still made a great splash. Nearly every automotive magazine ran in-depth articles on the new six, speculating what it heralded for future Detroit engines. The buff books were particularly excited about the optional four-barrel version of the new engine, which Pontiac advertised as the answer to exotic European engines.
The four-barrel OHC engine had the same displacement as its more mundane sibling, but had new intake and exhaust manifolds, a hotter camshaft, and a higher compression ratio. It was rated at 207 gross horsepower (154 kW) and 228 lb-ft (308 N·m) of torque, which was, as Pontiac advertising inevitably pointed out, more than many small-block V8s of the time. Chevrolet’s basic 283 cu. in. (4,638 cc) engine, for instance, was rated at only 195 hp (145 kW).
The four-barrel engine was marketed as part of a Sprint package that included stiffer shocks, side stripes, and other cosmetic details. Priced at $126.72, the Sprint package was available on any Tempest or Le Mans except station wagons. Pontiac marketed it as a European-style sports sedan, although most reviewers saw it as a sort of six-cylinder GTO. Naturally, the Sprint wasn’t as fast as the GTO, but its straight-line performance was more than adequate — 0-60 mph (0-97 km/h) took less than 9 seconds and top speeds of 115 to 118 mph (185 to 190 km/h) were possible. With less weight on the nose than a GTO, the Sprint also handled and stopped better. The hotter six was not particularly strong below 3,000 rpm, but it was tractable enough and many reviewers were entranced with its Jaguar-like growl.
Indeed, the Jaguar comparisons were tempting enough that Pontiac ad man Jim Wangers persuaded Doc Watson of Hurst Performance Products to install a Sprint engine and four-speed in a well-worn 3.8 E-Type. Hurst turned it over to Car and Driver, which found it somewhat slower than a healthy Series I E-Type, so Hurst added a trio of Weber carburetors and a few other shade-tree hot rodding tricks that brought the engine to a claimed 315 horsepower (235 kW). Despite Car and Driver‘s enthusiasm, the Pontiac-engined Jag didn’t inspire a raft of imitators, but it did attract a lot of attention, which was the point of the exercise. (The converted car was later purchased by Ford engineer Don Coleman, who substituted a 300 cu. in. (4,918 cc) Ford six for the Pontiac cammer.)
The publicity and favorable reviews were not enough to make the Sprint a runaway success. Total production for 1966 was fewer than 20,000 units, compared to nearly 97,000 ’66 GTOs. While the hot OHC engine was novel, it was not powerful enough to entice horsepower-crazed teenagers, and the few customers interested in fuel economy in 1966 usually settled for the base engine. (Pontiac claimed the Sprint engine was capable of 20 mpg (11.8 L/100 km), but a Popular Mechanics owner survey in 1966 found that even the base engine seldom exceeded 17.5 mpg (13.4 L/100 km) in normal driving.) Even Car and Driver, for all its enthusiasm for the concept, reluctantly concluded that the V8 was a more sensible choice for A-body. Despite the OHC engine, the Tempest/Le Mans Sprint was no sports sedan and many observers wondered if the hot six would do better in a smaller, lighter, sportier car.
By the time the Tempest/Le Mans Sprint entered its second model year, Pontiac was busily readying the Firebird for its mid-year introduction. When the Firebird went on sale in late February 1967, the 165 hp (123 kW) OHC six was standard, with the Sprint package as one of four engine options.
On paper, the Firebird looked like a much better home for the Sprint engine than the A-body Tempest, but the real-world results were less edifying. Although the Sprint engine was now rated at 215 horsepower (160 kW) and 240 lb-ft (324 N·m) of torque, most reviewers found the Firebird Sprint noticeably slower than the ’66 Tempest/Le Mans Sprint, particularly with the California emissions package. Part of the problem was the fact that the Firebird was not that much lighter than the Le Man despite smaller dimensions. Car Life‘s well-equipped 1967 Firebird Sprint was actually 40 lb (18 kg) heavier than their ’66 Le Mans Sprint hardtop coupe. The Firebird Sprint handled marginally better than its V8 counterparts did, but it suffered all the suspension infirmities of all early F-bodies, including excessive wheel hop, a choppy ride, and a tendency to lose composure on uneven surfaces.
As with the Le Mans, the Firebird Sprint’s greatest problem was price. Although the four-barrel engine package was not particularly expensive, at $105.60, the 285 hp (213 kW) 326-HO actually cost about $10 less and mated better with the automatic transmission that most buyers preferred. Fewer than 25% of Firebird buyers opted for either OHC six.
Pontiac planned to drum up some interest with a special performance edition known as PFST (Pontiac Firebird Sprint Turismo), a Camaro Z/28-style homologation special for SCCA competition. Developed by engineer Herb Adams, the PFST used a modified version of the Sprint engine fitted with three Weber 40DCN carburetors that protruded through the hood into a tall reversed scoop. The suspension was extremely stiff with stout anti-roll bars front and rear, giving excellent handling at the expense of a rather brutal ride. Pontiac let magazine testers drive the PFST prototype, but the new model didn’t make it to production. The triple Webers ran afoul of GM’s new ban on multiple carburetion and even after substituting a bigger Rochester Quadra-Jet, the modified engine was too loud to pass drive-by noise regulations.
Racing driver John Fitch, who had previously had a modest business selling modified Corvairs, developed his own tuned Firebird, also using the OHC engine. Unfortunately, the package was too expensive for most buyers. Fitch built only a handful of modified Firebirds, only one of which had the six-cylinder engine.
THE DECLINE AND FALL
Going from chief of Advanced to chief engineer and then general manager was a mixed blessing for John DeLorean. His increased authority also chipped away at his former autonomy — there was ever-increasing pressure to meet cost targets and adhere to conservative corporate policy. DeLorean’s clashes with senior management were seemingly endless, which made him many powerful enemies within the corporate hierarchy.
The OHC six eventually became another point of contention. DeLorean’s immediate superiors, GM group vice president Roger Kye and executive vice president Ed Cole (who became GM president in 1967), were always unhappy about its high costs. Although Mac McKellar had done everything possible to minimize those costs, including sharing some parts with the contemporary Chevrolet six, the OHC engine was still more expensive to build than its Chevrolet cousin. It also had higher warranty costs; while the timing belt itself was quite reliable, there were problems with premature camshaft wear and sticking valve lash adjusters. None of these issues was insurmountable, but they did nothing to win the confidence of an already skeptical corporate management.
For the 1968 model year, Chevrolet stroked its 230 cu. in. (3,769 cc) six to 250 cu. in. (4,095 cc). Pontiac did the same, but the Chevrolet’s new counterweighted crank was apparently not compatible with the higher-revving “cammer.” Designing a new crankshaft and connecting rods presented no great technical challenge, but it further reduced the OHC six’s already limited commonality with the Chevy engine, making the Pontiac engine that much more expensive to build.
Cole and Kye found the costs of the OHC six hard to justify, particularly given its modest sales; more than three-fourths of buyers opted for the V8, which cost less to produce. The tall OHC engine also posed some packaging problems: It would not fit in the engine bay of the second-generation Firebird without a prominent hood bulge. Cole finally ordered DeLorean to discontinue the cammer in favor of the cheaper Chevrolet engine. As with the Banshee, DeLorean fought to save the OHC engine, but it was to no avail.
In February 1969, DeLorean was promoted to run Chevrolet, replacing Pete Estes as general manager. His successor at Pontiac, Jim McDonald, was a production man, not an engineer, with little interest in either technical innovation or battling management. The OHC six was quietly dropped at the end of the 1969 model year. Development of the OHC V8s was canceled, as were a number of experimental versions of the six, including one with hemispherical combustion chambers. The focus of engineering development was shifting to emissions control and high-revving, high-performance engines seemed increasingly anachronistic.
The cancellation of the OHC six was unfortunate because less than five years later, the OPEC oil embargo sent Pontiac engineers scrambling to find smaller, more fuel efficient engines. Unlike Buick’s resurrected V6, whose tooling had been sold to Kaiser Jeep and then to AMC, the tooling for the cammer was probably long gone by then, leading Pontiac to develop the thoroughly undistinguished 301 cu. in. (4,942 cc) V8 instead. Had the OHC six survived, it probably would have done very well in the seventies. Even the Sprint might have found its niche, appealing to performance-minded buyers who couldn’t afford the insurance premiums on a GTO.