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Vintage Road Test: Putting a 1968 Chevelle SS396 To the Test at the Dragstrip

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Drew Hardin Jul 27, 2017
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“As the lights come down, you squeeze the engine towards six grand, slide your left foot off the clutch, stab the loud pedal between the last yellow and the green, and bang!—375 horses (a 425 Performance Rating via NHRA’s new system) launch you off the line for a near record run. Right? Wrong! At least that’s the way it was on every run we made with this month’s drag test vehicle, a ’68 Chevrolet SS396 Chevelle hardtop.”

Car Craft magazine’s John Raffa was obviously frustrated while testing Chevy’s all-new A-Body at the Irwindale dragstrip in November 1967. That frustration boiled right to the surface in the paragraph above, which opened his Drag Test in the magazine’s Feb. ’68 issue.

“Oh, the horses are there all right (just witness that ‘drive-in idle’ of the L78 engine option), but somebody back in Detroit forgot to couple ’em up to the drivetrain in the properly prescribed quarter-mile manner; so instead of a clean break away from the line and solid punch from the green on, we got a big jump, then a letdown—like ‘Bog City.’”

Raffa’s assignment wasn’t just a run-of-the-mill driving impression. One of his goals was to determine “where the Chevelle fit into NHRA’s 1968 plans.” Mounting a set of 8-inch Casler slicks meant the test Chevelle “would have to be placed … in SS/D, while it would fall into A/S if prepared for the Stock classes.” New NHRA rules for 1968 classified Stocks, Super Stocks, and Sports cars using the “aforementioned Performance Rating method, not according to weight and advertised horsepower figures as in the past.”

Archive 1968 Chevrolet Chevelle Ss396 Dragstrip Launch Front Alt 1 2/8

The existing SS/D record, 11.70, was held by “Wally Booth’s outstanding Camaro,” though Raffa felt “a more meaningful figure for our purposes is the old SS/E record, since its factor figures are much closer to the ’68 SS/D class than were the old SS/D marks.” Another Camaro, “that of Volpe-Pizzi-Rose … held that record at the end of the ’67 season at 11.98.”

Raffa’s low-14-second timeslips were a long way from record territory.

Some sleuthing revealed what was hampering the Chevy. For one thing, someone had spec’d the car with a highway friendly 3.08 axle ratio. “No wonder we had that bog off the line and a seemingly interminable wait between gear changes.”

There were other issues, too. At the strip, Raffa experimented with several different launch and shifting techniques to overcome the bog. He tried taching the motor up to 4,800 before releasing the clutch and gently rowing through the gears. He also did his “best Ronnie Sox-type” speed shifting. “But Casler’s tires were just too much for that blankety-blank gear in the rear.”

He also had trouble with the transmission itself, or, more accurately, the shift mechanism. On the track, the shifter got “hung” in Neutral between First and Second. “I had to get almost all the way off the power before I could make the shift.” On his next pass, “I waited out the bog and shifted a lot easier—kind of a compromise between my version of the Sox ‘explosion shift’ and your grandmother’s handling of the same apparatus. I got Second this time, but not without a lot of effort.”

Archive 1968 Chevrolet Chevelle Ss396 Dragstrip Launch Front 3/8

Why the “big hangup” between gears? “Nestled between the seats is a most familiar looking sight—the flat handle that has come to mean ‘Hurst’ in the minds of most do-it-yourself drivers. There’s even the familiar block lettering on the handle, only here it spells ‘Muncie.’ Too bad.”

But that handle “only controls the action,” he reasoned. “We had to look a little farther.” Putting the Chevelle on a rack, he went underneath and found “one of the wildest mazes of linkage it had ever been our mispleasure to encounter. Not only that, it was all tied to the crossmember, not the trans itself.” That meant that “when the engine torques under power, the linkage arms are strained at all kinds of angles … binding against the member and effectively closing the normal shift gates. The gate can only open again when you release the pressure on the gas pedal, relieving the twist against the shift arms.”

The upshot: “It looks as if your first purchase after buying your new Chevelle should be a positive shifter that mounts on the trans—Hurst or otherwise.”

He also recommended adding a “good set of headers” to the L78, like the Hooker headers that were added to his test car. “Then, of course, an engine blueprinting is in order, and you can go to work on the suspension, although we found that the factory-installed heavy duty suspension did an excellent job of handling all the gobs of torque the 396 puts out.

“After that, head for the strip and start looking for a new place to store all the ‘gold’ you’re about to win with your ’68 Chevelle.”

Archive 1968 Chevrolet Chevelle Ss396 Dragstrip Launch Rear 4/8

Photos: John Raffa, Dick Scritchfield, Petersen Publishing Co. Archive

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