In 1970, GM lifted all engine size caps for the A-bodies and all hell broke loose. Immediately, Chevrolet, Pontiac, Oldsmobile, and Buick proceeded to cram their biggest power plants into their respective intermediate car.

Тhe Gran Sport received a new design and a new engine. Just like the Skylark, it was based on, the Gran Sport received new sheet metal, partially shared with the Chevelle.

It lost the signature side curve, which was replaced by a thin straight crease. The grille was divided into two deeply recessed angled pieces wrapped in chrome trim. This emphasized the protruding nose and gave the front end some depth.

The hood scoops were redesigned to match the grille aesthetic and give the GS an aggressive, sporty feel. At the back, a conventional straight rear bumper replaced the previous curved design.

This was still a Buick after all, so the exterior styling remained conservative with just a few badges and mundane color options. The top two colors were Burnished Saddle (brown) and Bamboo Cream (brown).

Digested Grass Green was the 4th most popular…

Inside, you’d find a much more pleasant interior compared to the day’s muscle car. Vinyl seats were available in three styles – bucket, notchback, or bench. Options included a tachometer, speed alert, AC, tinted windows, power brakes – either drums or front disks and other goodies.

Of course, high-performance vehicles were treated to a fully-boxed perimeter frame and heavy-duty springs and shocks. The optional Rallye suspension added stiffer springs and shocks as well as thicker anti-roll bars and boxed rear control arms.

Speaking of high performance, for 1970 the Gran Sport was renamed GS455 and received a new monster of an engine – Buick’s 455 ci big-block V8.

The Buick 455 ci big-block produced record-breaking torque

The culmination of Buick’s engine development program was the 455 cubic inch, big-block V8.

To create it, Buick overbored the cylinders of its existing 430 engine – from a 4.1875-inch to 4.31-inch diameter. The nodular iron crankshaft and forged connecting rods were interchangeable between the 430 and 455 with unique cast aluminum pistons and heads for each model.

This was an interesting move, as it created a physically smaller and lighter engine, compared to other 455 versions within GM. Buick’s version weighed around 85lbs less than Chevy’s 454 V8.

The Buick 455 V8 produced 350 horsepower at 4,600 RPM and a stump-pulling 510 lbs-ft of torque at just 2,800 RPM.

If you had to define a classic muscle car engine, it would be a high displacement naturally aspirated V8 with massive amounts of torque and breakneck acceleration in a straight line. It doesn’t get any more muscular than Buick’s 455.

In fact, this was the most torque any American performance engine produced for the next 33 years.

Ford’s Boss 429 wasn’t even close – at 450 lb-ft. Mopar only reached 490 lb-ft. And other GM divisions got up to 500 lb-ft of torque. The Buick 455 was only surpassed by the Viper V10 in 2003. And guess what, it produced 2% more torque with 10% more displacement and an additional 2 cylinders.

Of course, torque doesn’t win races. An easy swap of the final drive ratio could get you the required torque at the wheels. Yet, the Buick 455 would press you down into your seat like no other engine of its time. And while it wasn’t the most powerful, its low weight and quick response compensated in real-world performance.

Starting 1970, the 455 engine would come optionally in pretty much every Buick on the market.

This thin-walled block was considered very advanced for its time. However, it wasn’t without its drawbacks. The lifter valleys proved to be a weak point and were prone to cracking when driven hard for prolonged periods.

Additionally, the crankshaft was only held in by two-bolt main bearing caps, which wasn’t enough to remain perfectly rigid. Finally, the engine featured an undersized oil system, which had difficulty keeping up at sustained high RPM.

1970 Buick GS455 Stage I

If launching first off the line wasn’t enough for you, Buick also offered the 455 with a Stage I package.

It featured cylinder heads machined to accept bigger valves – 2.12-inch intake and 1.75-inch exhaust. New smaller combustion chambers raised the compression ratio to 10.5:1. A more aggressive camshaft provided 316 / 340 degrees of duration and a 0.490-inch lift on both valves.

Bigger oil pickup tube, stiffer valve springs, heavy-duty radiator, and specially tuned 4-barrel Quadrajet carburetor supplemented the engine.

Just like with the GS400 Stage I, these upgrades brought just 10 more horsepower on paper, but everyone knew it was massively underrated.

While it never reached formal production, Buick did develop a Stage II upgrade for the 455 V8. One of the few factory prototypes was able to run a quarter-mile in 10.70 seconds at 123mph.

The world wasn’t ready for a 10-second factory car, but all parts were available as dealer-installed options. It is unknown how many, but without a doubt, some Buick fanatics specced themself a genuine death trap of a car.

The Supercar Shootout – Stage 1 vs Hemi Cuda

At the time, fewer than 3,500 Buicks were equipped with both the 455 ci V8 and the Stage I package.

When Motor Trend tested a 1970 Buick GS455 Stage I, weighing 3,800 lbs, on the track, they obtained a 13.38-second quarter-mile at 105.5 mph.

The same year Pontiac GTO achieved a 13.40-second quarter mile. The Hemi Cuda was further behind with 14 seconds – both tested by Motor Trend.

The GS455 Stage I was a rare sight, so its performance was mythical but largely ignored. Everybody who knew cars realized it was up there with the fastest, but maybe the Motor Trend guys got a lucky day or something. There are a few outliers in every crop.

However, in 1984, Muscle Car Review published an article that infuriated every Mopar enthusiast on the planet. The article proclaimed Buick GS455 Stage I was the 3rd quickest muscle car ever, trailing behind a 427 Cobra and 427 Corvette. The first and second place didn’t seem to matter. More importantly, a Buick – your dad’s car – was placed ahead of all legendary Hemi dragsters that came out of Chrysler.

This couldn’t be possible. Or so did Roy Badie thought when he wrote to the magazine, sending out an open challenge to every Buick owner:

“…the GS Buicks run like they’re tied to a tree!”

Well, Richard Lasseter – president of GS Club of America – took Badie up and the race was scheduled in 1985 at the Gainesville Raceway with exclusive coverage by Muscle Car Review for their inaugural Supercar Shootout series.

Hemis are legendary on the drag strip. Most people who followed the feud would easily put their money on Badie’s 1970 Plymouth GTX. Its race-bred 426 Hemi V8 produced 425 horsepower and 490 lb-ft of torque. The problem was, Badie had just recently obtained the car and didn’t have a chance to practice for a serious drag race. He experienced various difficulties – from fitting the right tires, to a problematic air cleaner.

On the other hand, Richard Lasseter purchased his 1970 Buick GS455 Stage 1 new from the factory. He had 15 years of experience behind the wheel of this particular car and had participated in and won a number of drag racing events. Lasseter knew exactly how to prep his GS to extract every last horsepower out of it, including chilling the intake manifold with bags of ice to increase air density for the run.

Both cars were very close to stock with minor modifications to compensate for their age and uneasy life.

Roy Badie lost that day and it wasn’t even close.

Quarter mile drag – Run 1

• 1970 Buick GS455 Stage 1 – 12.59 @ 108.56
• 1970 Plymouth GTX – 13.34 @ 106.63

Quarter mile drag – Run 2

• 1970 Buick GS455 Stage 1 – 12.30 @ 110.97
• 1970 Plymouth GTX – 13.03 @ 107.14

The original footage from the event is published by Hot Rod. You can read a digital version of the 1985 Muscle Car Review story at TeamBuick.com.

Of course, Mopar fans were outraged. The Hemi folk claimed Lasseter’s car had Stage II parts and was race-prepped specifically to beat the GTX.

Races are arranged to this day with mixed results. Both cars are fast enough and closely matched, so driver skill often dictates the outcome. The dispute is still not settled.

Yet, both Lasseter and Badie agree that the Buick was the faster car that day. With the race documented and etched forever into automotive history, that’s probably all that matters.

You are reading part 3/4 of The Story of The Luxury Muscle Car. Other articles in this series are available below:

1. The Story of The Luxury Muscle Car – Buick Gran Sport
2. 1697 Buick GS400 – Getting Serious About Performance
3. 1970 Buick GS455 Stage I – Faster Than a Hemi?
4. 1970 GSX – The Buick that Made Legends