Oddball LS6 Chevelle Hides A 12.2-Second Secret

LS6 Chevelle

The 1970 LS6 Chevelle is one of the most iconic Chevys in history, right up there with the ’55-’57 models, the ’63 Corvette split window coupe, and the ’69 Camaro. With 454 power, it had the highest advertised horsepower (450) of any muscle car of its era, and it built a rich history in drag racing.

David Povio’s  LS6 Chevelle SS454, however, could be considered something of an oddball among these cars. Yes, it is uncommon, with only 4,475 made, but what it does not have makes it as interesting as what it does.

LS6 Chevelle

The license plate tells only part of the story. It also has factory 4.10 gears in the 12-bolt Posi. (Photo by Jim Campisano)

It has 4.10 gears and an M22 “Rock Crusher” Muncie four-speed. Nothing too unusual there. But there’s no cowl hood and no stripes. The carb was encased in a twin-snorkel housing off the assembly line instead of an open element air cleaner. Inside, it was built with Malibu door panels, not those for an SS.

And all this is documented for the Atlanta-built Chevelle.

A lot of owners might have restored the car and simply socked it away for posterity. Or they might have added the cowl hood and band-aid stripes, etc. Not David Povio.

According to the owner, switching to the open-element air cleaner with the 4-inch tall filter is worth two-tenths in the quarter-mile — at least. Incredibly, he retained the A.I.R. emissions system. (Photos by Jim Campisano)

Less Is More

Povio had other ideas. He decided to leave the car the way Chevrolet built it from a visual standpoint, but take its performance to the next level while using all factory parts. The car competes in the Pure Stock Muscle Car Drag Race and the Florida Muscle Car Drags, where owners attack the strip on reproduction bias-ply tires with stock exhaust and intake manifolds, etc., and without the benefit of modern traction aids.

The car you see here is on the cusp on an 11-second time slip, running a best of 12.22 at 116.02 mph. This is not the first feature we’ve done on one of these Pure Stock cars. We covered this L89 Camaro SS396, too, and we can’t get enough of them.

Many people confuse the Pure Stock Drag Race cars with those of the unlimited machines of the Factory Appearing Stock Tire series, where lots of cubes rule the day. Not so in PSMCDR. No giant stroker engines or ported cylinder heads are allowed. A .070-inch overbore is permitted, but the stroke must be stock. Cylinder head and intake casting numbers must be factory correct. Even the exhaust manifolds have to be correct for the combination and no porting or internal modifications are allowed.

You are allowed to bump compression a point-and-a-half. The camshaft must be correct for the year, model, and horsepower claimed for the type of lifter (hydraulic or solid). Roller cams are forbidden. Duration at .050-in. lobe lift must be within one percent of factory specs. Lift at the valve must be within two percent of factory specs. Engines must be able to produce at least 16.0 inches of vacuum at 1,200 rpm, though some factory engines are given an exemption if they could not produce this much when new.

No soft-compound tires are allowed and the biggest you can go is one size up, so if your muscle car came with F70-14s, you are allowed G70-14s. These rules really put a premium on driving skill.

Povio’s engine was built within the confines of the rules. The block received a .060-inch overbore and now displaces 468 cubic inches. One major departure was the addition of a set of the optional L89 aluminum heads. There are documented examples of these heads on LS6 Chevelles, so PSMCDR rules allow them. Their biggest — perhaps only — advantage is weight savings, but there’s no question they aid weight transfer at the strip.

To make things harder on himself, David outfitted the engine with the original Air Injection Reactor system emissions controls, which means the outlets on his exhaust manifolds are more restrictive than they would be for a non-A.I.R. car.

When the late-1970-built Chevelle is in competition, he runs it with a factory-style open-element air cleaner with a tall four-inch air filter. This most definitely frees up horsepower vs. the dual-snorkel unit, and according to the owner, worth at least a couple of tenths in the quarter-mile.

All Business Inside

The four-speed’s factory Hurst shifter wraps around the flat bench seat in this SS. When David races it, the SS454 has much of the paperwork on display. A reproduction window sticker is in the left rear quarter class. Dealer-style paper floor mats cover the carpeting. The “Use Only Premium or Super Premium Fuel On This Car” warning label dangles from the cigarette lighter, just as it would have when the A-body sat on the floor at Ron Shafer Chevrolet in Anniston, Alabama.

This is the Chevelle's "race" trick, with paper floor mats and the Premium Fuel Only tag hanging from the lighter. The build sheet is on display on the passenger side of the instrument panel. (Photos by Jim Campisano)

Unlike a lot of muscle cars back then, the LS6 Chevelle had a tach mounted directly in front of the driver, to the left of the 120 mph speedometer. Redline was 6,500 and it went to 7,000. One other oddity on David’s SS is the door panels say “Malibu,” which is incorrect.

The only convenience option was an AM pushbutton radio, which was $61 extra, but David left out for now. Standard with the SS454 equipment package were dual exhaust, the domed hood, black-accented grille, power disc brakes, sport wheels with Wide-Oval tires, Astro Ventilations and a few other goodies. Front shoulder harnesses and head restraints were the only nods to safety. The trunk area is as clean as the rest of the car.

David gets a huge amount of enjoyment from banging gears on street and strip in this LS6 Chevelle. It is a show-quality vehicle that is on the cusp of 11-second elapsed times — and that is his ultimate goal. The quickest LS6 in PSMCDR history is Jim Lerum, who ran 12.21 at 115.32, which means he could better that this year.

Beware if you come across a plain-looking Cortez Silver LS6 Chevelle SS. It’s a lot meaner than its non-cowl hood and lack of Sport Stripes would let on.

About the author

Jim Campisano

Jim's had a wildly varied career, from newspaper, magazine, and Internet writing to TV production and YouTube videos. Now, he's back at his first love: Automotive content creation because words matter.
Read My Articles

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