In this edition of Muscle Car Milestones, the 1970 Chevrolet Chevelle SS is our featured powerhouse. Ask just about any muscle car aficionado his favorite muscle cars and chances are, the 1970 Chevrolet Chevelle SS ranks high on that list. In fact, many Chevrolet enthusiasts and collectors consider this car to be the marque’s zenith in terms of performance, styling, and horsepower. Stay with us as we look back at one of the most iconic muscle cars ever created.
“The past is gone. The future may never see a car like this. It is one of the brutes, and all it needs is a way of staying in contact with terra firma”. Steve Kelly, Hot Rod Magazine, May 1970
The Chevrolet Chevelle SS sported several new styling cues for 1970. The car’s modern design featured a new grille, hood, front bumper, and front fenders. Changes out back included new rear styling and taillights and backup lights integrated into the rear bumper. The interior featured a new instrument panel along with a new instrument cluster and controls. It was a new car for a new decade with aggressive styling to match its wicked attitude.
Chevrolet offered two Super Sport packages for 1970. Checking off Z25 on the options list got you a 396 cubic-inch engine with 350 horsepower and 415 lb-ft of torque. It set you back $445.55 but got you front disc brakes, special domed hood, sport wheels with wide-oval white-letter tires, and a black resilient rear bumper panel. Car and Driver got a 0 to 60 time of 5.8 seconds and ran the quarter mile in 14.41 seconds at 97.35 mph in this A-body cruiser.
For the 1970 model year, General Motors dropped their mandate that no engine larger than 400 cubic-inches could be installed in an A-body. Shelving this restriction opened up the opportunity for Chevrolet to drop two versions of the 454 big block under the Chevelle’s hood. The LS5 454 was rated at 360 horsepower and 500 lb-ft of torque. This engine came with features such as small oval-port cylinder heads, a Quadrjet carburetor, cast-iron intake manifold, and hydraulic camshaft.
The real deal was the LS6 version of the 454. Those in the know snicker when they open the hood and see the 450 horsepower sticker on the air breather. This number was grossly understated by Chevy, possibly to keep the pesky insurance companies at bay. It features an 11.25:1 compression ratio, mechanical valve lifters, high performance camshaft, and a Holley four-barrel carburetor. It was no slouch either. In their December 1969 issue, Motor Trend tested the Chevelle 454 LS6 and walked away with a 0 to 60 time of 6.0 seconds and a quarter mile time of 13.8 seconds running 97.5 mph. The Chevelle used in testing was equipped with a Turbo Hydra-Matic transmission, 3.31:1 positraction rear axle, and cowl induction.
Seeing this car coming up behind you in the rear view mirror is a bit intimidating. It’s like seeing the schoolyard bully coming your way. You know he’s going to kick your butt and take your lunch money but there’s not much you can do about it. During the same test, Motor Trend pitted the 454 LS6 against its crosstown rivals — the Ford Torino 429 Cobra and Plymouth Road Runner 440-6. In the quarter mile, the Chevelle beat the Cobra by 0.7 seconds and outgunned the Road Runner by 0.6 seconds. Those numbers aren’t staggering but it just goes to show how domineering the Chevelle LS6 actually was in its day.
Both the LS5 and LS6 were available with either a four-speed manual or a Turbo-Hydra-matic automatic transmission. And no SS is complete without the Cowl Induction package. This RPO ZL2 package features a vacuum-operated air flap on the back of the hood that feeds fresh air into the engine. This package also included hood and back deck stripes and hood lock pins.
Reviewers that drove this car when it was introduced knew it was special and that its time was short. Words like “supercar” and “earth mover” were used to describe its indomitable performance and bravado. With government regulations tightening around reducing emissions and with insurance rates totaling one-third the value of a car, the muscle car was on its way to extinction. The 1970 model year is considered by many to be the last year of the true muscle car. And the 1970 Chevrolet Chevelle SS is proof that Chevrolet intended to leave its signature on this bygone era with lots burned rubber.
Sources:
Chevrolet SS Muscle Car Red Book, Second Edition, Peter C. Sessler, 2001
Standard Catalog of American Muscle Cars, John Gunnell, 2006
Motor Trend Magazine, “A Date With Three Strippers”, December 1969, A. B. Shuman
Hot Rod Magazine, “Earth Mover”, May 1970, Steve Kelly
Specifications for 1970 Chevrolet Chevelle 454 LS6
Body & Frame
Type: welded perimeter with crossmembers
Body style: coupe
Engine
Powerplant: 90 degree OHV V8
Displacement: 454 cubic-inches
Horsepower: 450 @ 5,600 rpm
Torque: 500 @ 3,600 rpm
Oil capacity: 5 quarts
Valvetrain: solid lifters, .020-inch clearance intake and exhaust
Bore x stroke: 4.25 x 4.00
Compression ratio: 11.25:1
Bore spacing: 4.84 inches
Carburetion: single Holley four-barrel, 1.689-inch primary and secondary bores
Transmission
Manufacturer/Type: Muncie four-speed
Gear ratio:
1st: 2.20:1
2nd: 1.64:1
3rd: 1.27:1
4th: 1.0:1
Axle
Type: 4.11:1 rear axle gear with limited slip
Steering
Type: power-assisted variable ratio; semi-reversible, recirculating ball nut
Overall ratio: 18.7-12.4:1
Curb to curb turning diameter: 42.5 feet
Turns lock-to-lock: 2.9 turns
Brakes
Front: floating caliper disc
Rear: drum with integral vacuum assist
Suspension
Front: independent, short-long arm type with coil springs and spherically jointed steering knuckle for each wheel. Double-acting tube shocks, 1.00-inch piston diameter, Link-type stabilizer, .812-inch diameter
Rear: Salisbury axle with location by upper and lower control arms. Coil springs and 1.00-inch piston diameter tube shocks
Wheels & Tires
Wheels: 14×7 steel wheels
Tires: F70-14 Firestone fiberglass bias-belted
Exterior Measurements
Wheelbase: 112 inches
Length/Width/Height: 197.2/75.4/52.6 inches
Shipping weight: 3,759 pounds
Front track: 60.0 inches
Rear track: 59.8 inches
Performance
0 – 60 mph: 6 seconds
Quarter mile: 13.8 seconds
