This is why the 1970 Chevelle SS 454 LS6 was Chevy’s secret weapon for the Muscle Car Wars.
The 1970 Chevelle SS 454 LS6 – Chevy’s Secret weapon for the Muscle Car Wars.
Chevy had a secret weapon and it was the 1970 Chevelle SS 454 LS6. It’s 1970, the Muscle Car War was raging on, and the Big 3 (GM, Ford, and Chrysler) are all bringing out the big guns. All three manufactures are now installing their biggest cubic inch engines in their intermediate cars. Ford with the 428 Cobra Jet and the Boss 429 engines. Chrysler with the 440 Wedge, and the all-conquering 426 Hemi. Buick, Oldsmobile, and Pontiac were now offering 455 cubic inch (7.46 L) engines. Chevy needed to respond and respond they did.
Chevy’s 454 Engine
In 1970 GM finally lifted their midsize car 400 cubic inch (6.6 L) engine restriction. This cleared Chevy to use their new 454 cubic inch (7.44 L) V8 Engine in the midsize Chevelle. Chevy increased the 427 Mark IV Big Block to 454 cubic inches (7.44 L) by increasing the stroke. The new 454 had a bore of 4.25 inches (10.79 cm) and a 4-inch stroke.
The Standard engine for the Chevelle SS was the Chevy 396 Big Block V8 (Which was bumped up to 402 Cubic inches in1970). However, Chevy also offered 2 optional 454s V8 engines in 1970. The LS5, rated at 360 Horsepower @ 4,400rpms and 500 lbs/ft of torque @ 3,200 and the mighty 450hp LS6.
The 1970 Chevelle SS 454 LS6 Engine.
Chevy probably fired the final shot with the LS6. The LS6 454 V8 was the most powerful production engine offered in any of the American Muscle Cars of that era.
The 454 LS6 V8 was conservatively rated by Chevrolet. The advertised horsepower rating was 450 @ 5,600. However, the engine actually was closer to 500 horsepower. It also had colossal 500 lbs/ft of torque @ 3,600.
A cast-iron Mark IV big block with 4 bolt mains. The rotating assembly got a super-strong forged steel crank, lightweight TRW forged aluminum pistons, attached to forged steel connecting rods.
Heads were also made of cast iron and had a 109cc closed combustion chamber giving the engine an 11.25:1 compression ratio. Valves were 2.19” on the intake and 1.88” on the exhaust side, with rectangular ports.
The LS6 came with an aggressive CAM with solid lifters. The intake had a .520” lift and 316 degrees duration. And a .520” lift and 302 degrees duration on the exhaust.
Respiration can from a low-rise aluminum intake manifold and topped by a Holley 800 cfm vacuum secondary 4bbl carburetor. Fresh air was fed by an all-new vacuum-operated “cowl induction” hood.
Chassis and Drivetrain
Transmission and Rear Axle
The Chevelle SS 454 LS6 was available with 2 transmission options. The Muncie M22 (Rock Crusher) 4-speed manual and the 3-speed Turbo Hydramantic 400. A heavy-duty 12-bolt axle was standard with the buyer’s choice of 3.31 or 4.10 gears.
M22 Gear Ratios
- 1st Gear2.20
- 2nd Gear 1.64
- 3rd gear 1.28
- 4th Gear 1.00
- Reverse 2.26
TH400 Gear Ratios
- 1st Gear2.48
- 2nd Gear 1.48
- 3rd gear 1.00
- Reverse 2.00
The LS6 Chevelle’s got Power-assisted brakes, with 11” discs in the front and 9” drums in the Rear.
Chassis and Suspension
The LS6 was built on the GM A-body Chassis with a 112” wheelbase. The car was 201.2” long, 75.4” wide, and 52.6” high. It came with Heavy-duty suspension with front and rear coil spring and sway bars. Upper and lower A-frame control arms up front, and tubular shocks front and rear.
1970 Chevelle SS 454 LS6 Body and Styling
The Chevelle was all-new for 1970. The sheet metal was restyled, with sharper body lines. At the front, a new front Grill with a body-color center section, a new “cowl induction” hood with a vacuum-operated flap. And two racing stripes on the hood and rear deck lid.
At the rear, the Chevelle got new rectangular taillights mounted into a redesigned rear chrome bumper. This gave the Chevelle SS a more aggressive and meaner look.
The Chevelle SS 454 LS6 was available in 2-door coupe or 2-door convertible and was available in many color configurations.
Exterior Colors Options
- Astro Blue
- Autumn Gold
- Black Cherry
- Daytona Yellow
- Desert Sand
- Champagne Gold
- Classic White
- Cortez Silver
- Cranberry Red
- Gobi Beige
- Green Mist
- Fathom Blue
- Forest Green
- Hugger Orange
- Misty Turquoise
- Shadow Gray
- Tuxedo Black
The 1970 Chevelle SS 454 LS6 buyer had many interior options to choose from. He or she could order a simple no-frills interior with bench seats or a car with all the comforts. Some options included a special gauge cluster, bucket seats, center console, and power windows just to mention a few.
Interior Colors Options
1970 Chevelle SS 454 LS6 Performance
Out of the box, the Chevelle LS6 was a screamer. With the massive 500 lbs/ft of torque one needed to be careful with the accelerator pedal. Stomp it too hard and you would be melting those 1970 factory bias tires. Tested by popular magazines of the day. The LS6 was consistently in the low 13 seconds on the quarter-mile, and crossing the line at close to 110 mph (177.03 km/h). This from a car weighing just about 4,000 lbs. With modern tires, the LS6 would certainly be in the high 12s.
1970 Magazine Tests
Car Craft Magazine: 13.12 seconds @ 107.81 MPH
Duper Stock & Drag Racing: 13.2 seconds @ 106 MPH.
Hot Rod Magazine: 13.44 seconds @ 108.17 MPH
The 1970 Chevelle SS 454LS6 was available with many options. Pricing Started at around $3,600 for a 2-door coupe and $3,875 for convertible models. By adding available options price could get well over $4,000. In 1970 that was definitely not the cheapest Muscle Car available.
- Starting Price 2-Door Coupe: $2,862.00
- Starting Price Convertible: $3,009.00
- Z15 454 SS Package: $503.45
- LS6 454 Engine: $263.30
- Chevelle Total Production 1970 633,944
- 1970 Chevelle SS396 Production 53,599
- 1970 Chevelle SS454 LS5 Production 4,298
- 1970 Chevelle SS454 LS6 Production 4,475
1970 Chevelle SS 454 LS6 specs
Engine: Chevrolet 454 cubic inch (7.44 L) LS6 Mark IV Big Block.
Power: Rated at 450 @ 5,600 and 500 lbs/ft of torque @ 3,600.
Transmission: 4-speed manual or 3-speed automatics.
Layout: Front-engine, rear-wheel drive.
Body Type: 2-Door Coupe or Convertible.
Curb Weight: 3,836 lbs
Dimensions: 201.2” long, 75.4” wide, and 52.6” high
The Chevelle was one of the best-selling cars ever for Chevrolet. With production reaching over 600,000 in for the 1970 model year. However, only 4,475 Chevelles were built with the fire-breathing torque monster LS6 Engine.
1970 was the high point of the 60s and 70s Muscle car horsepower wars. The 454 LS6 option was only offered in the Chevelle for one year. Due to new emissions legislation, unleaded fuels, and rising insurance costs all car makers were forced to reduce engine compressions in 1971. This was the start of the end of the super high horsepower muscle car engines of that era.
The 1970 Chevelle SS 454 LS6 is a top contender for the best classic American Muscle Car.
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Watch 2 classic videos of the 1970 Chevelle SS454 LS6.
Video 1 The 1970 Chevelle SS454 LS6 By Car and Driver.
Posted on YouTube By: HistoryKrell
Video 2 The 1970 Chevelle SS454 LS6 By Motor Trend American Classics.
Posted on YouTube By: HistoryKrell
Video 1 Transcript
The 1970 Chevelle SS 454 LS6 By Car and Driver.
Narrator: The muscle-car era 1970, but the street fighters were still on the scene. Even with rising insurance rates and government smog regulations pressing. In 1970 was the year Chevrolet bolted huge torque and huge displacement into the Chevelle, the 454 LS6.
The significance of the LS6 option for the Chevelle Super Sport was more than just horsepower. Its appearance in 1970 marked a real change in thinking at General Motors.
Tony Swan (Car & Driver Senior Editor): That was the first time, that was when GM finally relaxed its rule about putting big motors in their intermediate sedans. It was the A Body Car, but when they had their permission to put a motor of more than 400 cubic inches (6.6 L) displacement into a GM intermediate-sized car. They said okay let’s get the biggest one we can, and they did.
Narrator: Tony’s predecessors at the magazine agreed the new rule made sense. When they wrote there were engines and there were cars. It was just a matter of putting the two together.
The new engine for the Super Sport was a 454 cubic inch (7.44 l) monster drilled out of the Mark IV block. On top modified heads, sported huge intake and exhaust valves. And the key components were not from the GM parts bin.
Chuck Roskovich (Chevelle Collector): The LS6 had a steel alloy crank which was cross-drilled for better oiling. Also, TRW forged aluminum pistons, and 11.25 to 1 and a compression ratio, Holley 780 carburetor, aluminum intake, deep grooved pulleys. It also came with 450 horsepower which was the big difference as well as five hundred foot-pounds of torque.
Narrator: 450 horses was the conservative GM rating, real-world figures put the LS6 number closer to 500, matching the massive torque curve. Something that left a big impression on drivers of the day.
Tony Swan (Car & Driver Senior Editor): What they remember from that era is that these things really made torque. Cuz you’re talking about big-inch motors. And torque is what gets you out of the hole, and torque is what shred your tires, if you want to do that. A lot of guys did.
Narrator: Working hard to not shred the tires, the car and driver testers posted 0 to 60 times of 5.4 seconds and clicked off the quarter-mile in 13.8 at 104 miles per hour. The cowl induction hood option ran on engine vacuum. When the throttle dropped it opens to gulp cold air from the high-pressure area, at the base of the windshield. The exhaust ran through dual high flow mufflers, to resonators that sweetened the sound, before exiting through factory installed Chrome tips.
Power was feed into a manual four-speed Muncie or a Turbo 400 automatic transmission. The SS stood on a sports suspension option, braking was front discs, paired with rear drums. The 454-option added more than $1,000 to the price of the Super Sport. Yet inside the LS6 remain typical Chevelle for the day. Bucket seats, split by a console in front of a rear bench. The driver facing an instrument cluster with a 120 mile per hour speedo, flanked by a tack and a clock.
But all the excitement created by GM’s new engine rule would only last one year. The big blocks would stay in intermediates for 71. But new emissions controls saw compression ratios dropped to 9 to 1 for unleaded gas. The LS6 gave way to the cleaner LS5 454 but gave up 100 horses in the changeover.
Rising insurance rates also began to take their toll on buyers. Sales dropped to an all-time low for the Super Sport that year and production was halted after 1972. But, for one year GM’s LS6 Chevelle stood out as a true factory supercar. At the end of the era of cheap gas, monster engine, and go power for the street.
Now in the hands of collectors preserving our muscle car passed.
Video 2 Transcript
The 1970 Chevelle SS 454 LS6 By Motor Trend American Classics.
Narrator: Now from the Motor Trend archives its American classics. Brought to you by classic wax, take care of your pride with classic wax. “Love, Honor, Polish”.
Stu Maddux (Motor Trend Television): The performance starts as soon as you are seated. That’s how an ad for the 1970 Chevelle SS 454 LS6 once read. But as far as we can tell that is Chevrolet’s marketing team employing the art of understatement. Because this car right here has the highest factory horsepower rating of any muscle car ever made.
Chevelle Super Sport 454 cubic inches, 450 horsepower, and it’s all at the push of a pedal for this man.
Alan Tweedie (Chevelle Owner): They’re beautiful cars, I think.
Narrator: there are a lot of Chevelle lovers who consider this the model to aspire to. A 1970 Super Sport with 58 more cubic inches than the closest Chevy engine to it. Allen drove by a neighbor’s house every day watching this car from afar.
Alan Tweedie (Chevelle Owner): Out there by where we live, the car sat under a tree for 10 years.
Narrator: Then his neighbor got hitched.
Alan Tweedie (Chevelle Owner): He got married, and his new wife decided it had to go.
Narrator: So, after restoration Allen is the owner of an Astro Blue Chevelle with the highest factory output engine ever created.
Alan Tweedie (Chevelle Owner): The 375 horse 396 was the next step down, which was respectable.
Narrator: And very popular, there was the even a rarer LS5 version of the 454 that rated at 360 horsepower. Nothing like the 450 available under here.
The LS6 has 11.25 2:1 compression heads, an aluminum intake, special solid lifter cam. And it was teamed up with a huge 780 CFM Holley carb. All for the price that makes Muscle Car fanatic shed a tear today.
Stu Maddux (Motor Trend Television): Back then would you paid an extra two hundred sixty-three dollars. If you knew enough to order the 450 horsepower LS6 version of a Chevelle, you knew you were in for one fiery ride. Because Chevelle’s tested with the LS6, had run the quarter-mile in just less than 13 and a half seconds.
Narrator: In fact, in 1969 Motor Trend put a prototype Chevelle with the SS 454 option up against two other supercars of the day, a Plymouth Roadrunner, and a Ford Torino Cobra.
Editors wrote that they couldn’t help but be impressed by the Chevelle it was certainly the strongest the most super of the three.
But don’t let the engine overshadow the rest of this machine. There’s a few unusual options that make this a rare one. These are fiber-optic turn indicators.
Alan Tweedie (Chevelle Owner): I think that was a twenty-six dollars and thirty-five saying option back then.
Narrator: But the really interesting option is a little farther up on the hood. It’s this cowl induction system, it’s a rear-facing scoop that has a vacuum-actuated flapper.
Alan Tweedie (Chevelle Owner): What happens when you match the accelerator, the motor loses vacuum, flap comes up and pulls in fresh air.
Narrator: Check it out as he flours it for us. The air comes from a relatively high-pressure area at the base of the windshield. Oh yeah, it looks real cool too!
Alan Tweedie (Chevelle Owner): It’s pretty neat to see flap come up.
Narrator: And what a sound from the entire package, a sound that would start to be watered down after 1970. But this Chevelle could still walk on water today.
Alan Tweedie (Chevelle Owner): It shines, it’s pretty.
Stu Maddux (Motor Trend Television): For Chevelle lovers, the LS6 with Chevrolet’s crowning achievement then came concerns over air pollution and higher insurance premiums. So, this was the last year that they made that particular engine.
Now if you ask people who have ever driven a car with an lS6 in it. They’ll tell you a different reason for why they stopped making them. You can’t improve on perfection.
Alan Tweedie (Chevelle Owner): I’ve chased it for ten years and now I’m going to hang on to it.