A Very Rare ’70 Chevelle LS6 Convertible Is Made Right

At this point, Chevy’s 1970 LS6 Chevelle requires no introduction: with its rectangle-port heads and 2.19/1.88-inch valves, high-lift cam, forged crank and rods, 780-cfm Holley carb, and more, Chevy rated its 454-cube LS6 at an audacious 450 horsepower. That’s bigger than anything any other company advertised in a passenger car, full stop, until the end of the millennium. Just 4,475 LS6-equipped A-bodies were made for 1970, and they remain the stuff of legend—arguably the pinnacle of the muscle car movement.  

Alas, there are no known production breakdowns to give us an accurate number on how many LS6 Chevelle convertibles were made; Chevy’s records only kept the number of engines built in the Tonawanda, New York plant, not what vehicles they ended up in. That said, no credible estimate we’ve seen puts production much above a hundred units; Dan Carr’s noted Chevelle poster listing production numbers based on extrapolated figures suggests a mathematical probability of 95 built and noted collector car expert and appraiser Colin Comer estimated between 17 and 50 LS6 convertibles built. However low it is—and let’s face it, anything built in double digits is pretty low—the number of LS6 ragtops that have survived the five and a half decades since production is even lower still. Most estimates hover around two dozen or so extant. Of that relative handful of ’70 LS6 ragtops, there’s exactly one known to have been built in Cortez Silver with a red interior. This one. 

It was a well-optioned beast from new. Any LS6 Chevelle required the $503 SS 454 option as well as the $263 LS6 package. Beyond the striking color combination and the TH400 transmission, it had the Cowl Induction hood, a 3.31:1 axle ratio with Positraction, power steering, tilt wheel, bucket seats with console, tinted glass, power top, and more, bringing it to nearly a $5,000 MSRP. That’s base Corvette coupe money, for a Chevelle—albeit a Chevelle with an engine that even the Corvette didn’t get that year, and which let the atmosphere hammer your hairline at speed. 

Fred Cini of Wasaga Beach, Ontario, Canada, happily recalls his younger years tearing around the province in his four-speed Astro Blue LS6 coupe, but says he always wanted a convertible. When he found this example in an online auction in 2018, he pulled the trigger. He knew going in that what he was buying was real, but wasn’t quite right. It had previously been restored back in 2006, though its prior history was lost. But as always with a quality restoration, it’s all about the details. Fred noted that the distributor, alternator, and steering wheel were wrong, that there were lots of reproduction parts on board, and that the body panels didn’t line up as they should have. Fred purchased the Chevelle knowing it was going to have to be redone to be made right. 

For this task, he turned to the combination of MuscleCar Restorations and Design (MCR) in Pleasant Plains, Illinois, and Super Car Restoration of Clymer, Pennsylvania. Jamie Cooper at Super Car Restorations (SCR) explains: “We take care of anything with paint. We started with the frame—those components are then delivered to Rick Nelson at MCR. He reassembled the painted suspension components and added the mechanicals. We get the chassis and add the bodywork. Then it goes back to Rick, and they do the glass, the interior, and the final assembly work.” Our east-of-the-Mississippi geography is a little rusty, but that sounds like an awful lot of back and forth between states that don’t border each other. “It is,” said Jamie, “but we meet in the middle, in Ohio, which is a five-hour trip for each of us. We’ve done multiple cars this way, and we’ve never hauled empty; Rick would get one from us, and we’d have one for him. It all works out.” 

Once the components were doled out to their respective shops, Jamie at SCR machine-stripped the body with a DA sander, while the floors were sandblasted down to bare metal. “It wasn’t too bad—it had been restored ten or twelve years prior—it just wasn’t that good of a restoration. There was a lot of filler on that car.” (Something referring to the previous work as “lipstick on a pig” may have been uttered, though our tape transcription fluttered, so we can’t be sure.) 

The only body panel that was replaced was the decklid, although Jamie discovered that he needed to work on every single body panel to make things right. Once the minor issues were finessed, Jamie used a skim coat of Evercoat Rage Ultra filler over a suite of PPG-family paint and primer products: DP90 (black) epoxy primer, which was then sanded smooth starting with 80-grit paper, working up to 150-grit and finally 220-grit paper. This was then primed with three coats of PPG VP2100 polyester primer, blocked with 150-grit and 220-grit material, followed by ECP urethane primer-surfacer, which was subsequently blocked with 400-grit paper and two coats of ECS sealer. The two-stage paint system used three coats of waterborne Envirobase paint, and four coats of EC550 clear; this was then wet-sanded with 600-, 800-, 1000-, 1500-, 2000-, 2500-, 3000- and 5000-grit material, with a final polish using Meguiar’s products. 

Jeff Mackay of Mackay Engines in Rochester, Illinois, handled the engine rebuild. The block, cast in November 1969, is missing the block code on the deck as it had been decked during a previous rebuild; beyond a .030-inch overbore, it remains stock, with 11.25:1 compression. A Gardner dual exhaust completes the transformation. Dyno results indicate 460 horses at 5,400 rpm—ten more than advertised—and torque numbers within a rounding error of the original 500 lb-ft. The TH400 isn’t original to the car, but has been built to behave as it would have by Steve Bernotas of Steve’s Transmission in Springfield, Illinois. 

Beyond refinishing, that full-frame chassis was equipped with Chevy’s F41 suspension—heavy-duty shocks and anti-sway bars front and rear. Rather than cheat with a suite of invisible aftermarket solutions, Carl directed the builders to get NOS parts where they could—including NOS ball joints and shock absorbers. The factory AO-code 14 x 7-inch wheels remain, wrapped in a reproduction set of F70-14 Goodyear Polyglas rubber. 

Inside, the Auto Custom Carpets rug and Legendary Auto Interiors seat covers count as reproduction pieces, but all else—the dash, gauges, wiring, console, rear arm rests—were brought back to new. The incorrect three-spoke steering wheel was tossed in favor of a correct two-spoke piece, and the steering column was refinished in its proper black. 

The result? Mile-deep paint, factory-issued manners, parts that look like they came from 1970 inside and out, and panel gaps you could roll a ball bearing down without losing it. It debuted at the Muscle Car and Corvette Nationals in Chicago in November ’22; to the surprise of no one who has read this far, it received MCACN gold. Not bad for a debut. That was the weekend that Fred first saw the completed car, and where he took delivery of his LS6 convertible and brought it home to Ontario. That award, judged by the people who know these cars best, only underscores Fred’s attitude toward his LS6 Chevelle ragtop: If it’s the only one out there, it’s gotta be right. 

specifications – 1970 Chevrolet Chevelle SS 454

PRICE 

Base price: $2,919 

Options on car profiled: SS 454 package ($503); LS6 engine ($263); power front disc brakes ($65); F41 heavy-duty suspension ($29); AM pushbutton radio ($61); power steering ($100); Positraction limited-slip differential ($43); F70-14 white-letter tires ($62); 

Soft-Ray tinted glass ($43); tilt steering wheel ($45); console ($54) 

ENGINE 

Type: Chevrolet Mark IV “big-block” OHV V-8; cast-iron block and cylinder heads 

Displacement: 454 cu.in. 

Bore x stroke: 4.25 x 4.00 in 

Compression ratio: 11.25:1 

Horsepower @ rpm: 450 @ 5,600 

Torque @ rpm: 500 lb-ft @ 3,600 

Valvetrain: Solid lifters, stamped-steel rocker arms 

Induction system: Holley 780-cfm vacuum-secondary four-barrel; aluminum low-rise, dual-plane manifold 

Ignition system: Delco-Remy breaker-point distributor (#1111437)  

Exhaust system: Cast-iron exhaust manifolds, dual pipes, mufflers, and resonators 

TRANSMISSION 

Type: GM Turbo-Hydramatic 400 three-speed automatic 

Ratios: 1st/2.48:1 … 2nd/1.48:1 … 3rd/1.00:1 … Reverse/2.07:1 

DIFFERENTIAL 

Type: Chevrolet 12-bolt with Positraction limited-slip 

Ratio: 3.31:1 

STEERING 

Type: Saginaw recirculating ball with power assist 

Ratio: 16:1 

BRAKES 

Type: Hydraulic front disc/rear drum with power-assist 

Front: 10.94-in rotors, single-piston calipers 

Rear: 9.5 x 2-in drums 

SUSPENSION 

Front: Independent; ball-joint type with coil springs, AC Delco shocks, anti-sway bar 

Rear: Solid axle with four-link upper and lower control arms, coil springs, AC Delco shocks, anti-sway bar 

WHEELS & TIRES 

Wheels: GM styled stamped steel 

Front/Rear: 14 x 7 in 

Tires: Goodyear Polyglas bias-ply 14 raised-white-letter 

PRODUCTION 

Chevrolet built 4,475 LS6-powered Chevrolet intermediates for the 1970 model year. Further breakdowns by body style and transmission are unavailable.  

PERFORMANCE* 

0-60 mph: 6.1 sec  

1/4-mile ET: 13.44 sec @ 108.17 mph 

_{* Source: May 1970 Hot Rod test of a 1970 Chevelle SS 454 coupe equipped with an LS6 and a four-speed.} 

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