1967 Chevrolet Chevelle SS 396: The 375-Horse Engine That Wasn’t in the Brochure

Robert Schilling’s July 1967 Motor Trend test, “Tres Chevelles,” ran the magazine’s hottest SS 396 down the drag strip on the first clear day after a week of rain. It was a 375-horsepower hardtop with a four-speed. The magazine’s caption explained where the extra power came from: “The 375-hp is dealer option on 350-hp engine.” The price list made the point in dollars. It charged $475.80 for the 375-horsepower engine and footnoted the figure as the total cost of parts to convert a 350-horsepower engine. By Motor Trend’s account, the 375-horsepower SS 396 was something a dealer built from a 350-horsepower car. Chevrolet’s 1967 brochure did not mention it at all.¹

The brochure’s SS 396 had two engines. It offered a 325-horsepower Turbo-Jet 396 as standard and a 350-horsepower version as the option. The 350 figure was itself a change. The same L34 had been rated at 360 horsepower in 1966 and returned for 1967 at 350, with torque listed at 415 lb-ft against the previous 420. ChevelleStuff’s engine table carries the L78 for 1967 as well, but it describes the engine as a late, unannounced option and borrows its 1966 rating of 375 horsepower for lack of 1967 data. Motor Trend’s specification panel printed the 375-horsepower engine’s torque as “NA.”^2,3,1

Chevrolet’s option report still counts a factory L78 for the year: 612 installations, listed at $237.00. Against the 63,006 SS 396s built, that is fewer than one in a hundred, a steep fall from the 3,099 L78s of 1966. The two kinds of evidence describe two different routes to the same horsepower, and neither replaces the other. The option report records factory-installed L78s. Motor Trend’s car documents a dealer conversion, priced as a parts total. How the 612 factory engines were ordered, and from what date, is not documented.^2,3,1

The SS 396 itself held its place as a separate series, in sport coupe and convertible form, still with no SS 396 El Camino. Standard equipment was the same honest package as before: a bench seat, a heavy-duty floor-shifted three-speed and only a speedometer, clock and fuel gauge. Motor Trend listed the SS 396 hardtop at $2,875. The L34 was $105.35 and the Turbo Hydra-Matic $231.35. The magazine’s El Camino carried the 325-horsepower 396 as an option on a Custom V8 that listed at $2,615, because the SS 396 name did not yet extend to the pickup.^2,1

Buyers bought fewer SS 396s than in the launch year. The reference tabulation lists 59,685 sport coupes, including 302 for export, and 3,321 convertibles, including 14 for export, against 66,843 and 5,429 in 1966. Convertible output fell by nearly 40 percent, while coupes fell by about 11 percent. Across a Chevelle line of 403,963 cars, El Camino included, about one in six was still an SS 396. The step-up engine found fewer takers too. The option report counts 17,176 L34s, a little over a quarter of SS 396s, against about a third the year before.^2,3

What 1967 added was mostly chassis and driveline. Front disc brakes were new to the option list, not limited to the SS 396, and required the rally wheels. They went into 5,153 Chevelles at $79.00, about one car in 78 across the line. The three-speed Turbo Hydra-Matic appeared in the Chevelle option report, recorded on 13,272 cars. Motor Trend said it was available only with the 396s. The four-speeds remained the enthusiast’s choice, with 48,354 M20 wide-range and 12,886 M21 close-ratio units line-wide. Chevrolet also counted 5,182 3.73:1 axles, 2,917 3.55s and 803 3.70s.^2,1

Schilling’s results separate the three configurations cleanly. The 325-horsepower SS 396 hardtop, with Powerglide and a 3.07:1 axle, ran 0-60 mph in 7.5 seconds and the quarter mile in 15.9 at 89.5 mph. The 375-horsepower four-speed car, with a 3.73:1 axle, Firestone Wide Ovals and front discs, managed 6.5 seconds and 14.9 at 96.5, running on a damp strip. Schilling judged that a full second understated the real gap, because the milder car had run on a bone-dry surface. The 325-horsepower El Camino with Turbo Hydra-Matic and a 2.73 axle ran 7.4 and 15.7 at 90. Economy followed power: 11.2 to 17.8 mpg for the mild SS, 8.8 to 13.0 for the hot one and 12.5 to 19.0 for the pickup.¹

The new brakes got a real test. From 60 mph the disc-braked 375 car stopped in 169 feet and the drum-braked 325 car in 165, a four-foot gap Motor Trend called nominal and expected to disappear once the discs’ fade resistance came into play over several runs. The magazine still called disc brakes “a bargain option.” The El Camino needed 234 feet, its light rear end trying to pass the front, a result Schilling blamed on weight distribution rather than the brakes. He praised the SS 396 as the first GM intermediate the staff had driven that was free of rear-end “jello-roll,” and he placed the tachometer on the left of the dash, where it hid the gas gauge.¹

Motor Trend also weighed the cars and found an oddity. On a certified truck scale with 20-pound graduations, all three weighed essentially the same, although Chevrolet’s own specifications showed an 80-pound difference between the SS 396 and the El Camino. The magazine offered no explanation, and the discrepancy stands. Its closing advice was plain: if a buyer wanted power along with polish, any of the 396 Chevelles would do. The same test, read in one sentence, shows a 1967 Chevelle whose most powerful combination was documented by a magazine and a dealer’s parts total rather than by Chevrolet’s own sales literature.¹

The ambiguity did not last. For 1968 Chevrolet redrew the Chevelle and gave the SS 396 a third body, the El Camino, and the L78 appeared in the option report as a $237.00 choice installed in 4,751 cars. That was nearly eight times the 1967 count. The M22 close-ratio four-speed and Turbo Hydra-Matic were both listed as SS 396-only equipment. The 1967 car, with its disc-brake option, first Turbo Hydra-Matic and half-documented 375-horsepower engine, was the bridge between the launch car and that fuller 1968 order book.⁴