It's no doubt that General Motors had built some real street brawlers leading up to 1970. The problem was they had imposed a 400 cubic limit upon their intermediate line. Outsiders like Yenko, Hurst, and Nickey to name a few had found ways around this rule. Weather it be ordering the cars from the factory sporting the bigger cubed engines through COPO programs or buying factory cars and making the swap themselves. They made some of the nastiest "super cars" of the era.
GM cut out the middle man in 1970. In what many would refer to as the pinnacle year of muscle cars, GM removed the 400 cubic inch limit and unleashed a portfolio of menacing street machines.
Everyone is well versed in the 454 Chevelles and 455 GTOs of 1970. Enthusiasts know what resided under the hood of the 70 Olds 442. Buick is what the principle or engineer drove but they decided to make a statement for 1970 as well.
Buick released the GS, short for Gran Sport, in 1965 on the Skylark "A" body to try and entice performance minded youth to their otherwise geriatric labeled brand. In 65 the GS 400 was introduced. Even though the 350 would become another engine option for the GS the 400 remained the top of the food chain until 1969.
Knowing of the rule change and dealing with an aged engine design. Buick's engineers got to work developing the all new for 1970 455 engine in 1969. The 455 would take on the task of eliminating the 400 and 430 cubic inchers and motivating the intermediate and full size lines.
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(1970 Buick GS 455 Stage 1)
The GS 455 as it would become known was all new for 1970. The 3.90" cylinder bore housed cast aluminum pistons that where mated to forged connecting rods. Buick added a nodular iron crankshaft with a 4.312" stroke. The heads containing 2" intake and 1.625" exhaust valves helped yield 10.1:1 compression. The hydraulic bump stick had an intake/exhaust lift of .389/.460 inches and a duration of 290°/322°. Air was fed through a cold air induction system to the 750 cfm Quadrajet. Spent gasses exited via cast iron exhaust manifolds and dual pipes. The package produced 350 horsepower and a tire melting 510 lb-ft of earth moving torque at a low 2,800 rpm. Only a 500 cubic inch Cadillac could best the torque number with 550 lb-ft for 1970 but we're talking about muscle cars not highway cruisers.
If you were looking for more excitement you could opt for the Stage 1 455 for a paltry $115. The Stage 1 shared the same block and rotating assembly but gain better flowing heads featuring 2.12" intake and 1.75" exhaust valves and stiffer springs. The camshaft saw an increase in size as well with lift at .490" and a duration of 316°/340°. A larger 5/8" oil pick up tube helped distribute ample lubrication throughout. As well as a bump to 10.5:1 compression. The Stage 1 option also mandated the heavy duty radiator. The added goodies brought horsepower numbers to 360 and torque was untouched.
The GS 455 weighed in at 3,750 pounds but in Stage 1 trim managed a 13.38 second pass at 105.50 mph with Motor Trends shoe. Motor trend was skeptical of the 360 horsepower rating and wrote that it was "some kind of understatement of the year." 0-60 times would fall in the 6.5 second range.
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Even with all that power ahead of you the standard transmission was the heavy duty 3 speed. While most opted for one of the two available 4 speeds, the wide ratio M20 and close ratio M21, the M40 Turbo Hydramatic 400 automatic could also be had. The Stage 1 included a larger clutch though.
Torque was moved rearward to the B.O.P. 8 1/4" 10 bolt. While posi was optional on the GS 455 it was standard on the Stage 1. Interestingly, the Canadian built GS 455s received Chevrolet's beefier 12 bolt. While 3 and 4 speeds had a rear gear of 3.42:1 standard, the automatics had a highway friendly 2.93:1 in base GS 455s. Stage 1s came standard with 3.64:1 unless A/C was added in which case the gear set was 3.42:1. Both the standard and Stage 1 455s could be ordered with 3.91:1 gearing. Wheels and tires could be as budget minded as the standard 14x6.5" wrapped in black wall G78-14s. To the optional upscale and sporty chrome 15x7" five spoke sport wheels wearing Goodyear G60-15s.
The Chassis was a 115" wheel base fully boxed perimeter frame. The front suspension consisted of independent coil and the rear was 4 link riding on coils as well. For a tighter, road hugging feel you could check the box for RPO F41 Rallye Ride Control Package. For $15.80 you gained a larger front anti roll bar. The addition of a rear anti roll bar. "Firm Ride" rear springs and "Firm Ride" shocks on all four corners. As well as the addition of boxed lower control arms. Stage 1 cars got reinforced upper control arms as well. Manual drum brakes were standard fare but power assist and 11" disc brakes were optional.
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(GS 455 convertible sporting optional 15x7" chrome five spokes)
Keeping with the all new for 1970 theme, the body saw a major redesign. There was no longer a "Sweepspear" hard body line or trim, rather a more refined crisp body line just below the belt line. The concave rear bumper of previous years was replaced with a straight piece for 70. The GS only deep recessed blacked out grille was also new as well as narrow horizontal rocker panel trim with two thin red stripes. The only stripes that would be available on the GS not including the GSX. The cold air induction hood was revised with larger ducts. The exterior was available in 14 colors and could even be special ordered on Riviera colors. Hardtops had no less than 12 interior colors with three different seating arrangements. You could order your GS with the standard bench seat, Strato bench or with the Strato bucket seats. Convertibles were offered with only seven of the twelve interior colors. Standard instrumentation was viewed through three square ports with round gauges. One could option up to a tach or clock. As well as power windows and locks. Three spoke sport wheel and air conditioning. A consolette was available with the manuals. Only the automatic cars could receive a full length console as long as buckets were ordered.
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Buick made an attempt at not catering to the successful business man and rather the gear head that wanted some muscle and luxury. Family sedans and standard Skylarks out sold GS performance vehicles hands down. In all for 1970 Buick produced 8,732 GS 455 hardtops and 1,416 GS 455 convertibles. Of those a mere 2,865 orders came in for Stage 1 hardtops and 232 convertibles got the Stage 1 goodies. With a base price of $3,514.01 and an option list that could easily propel you towards a $5,000 muscle car, it's a wonder why more people didn't want luxury muscle.
Buick experimented with a factory Stage 2 option but scrapped it in favor of making it an over the counter package of which around 75 were sold.
The term "Not your grandpa's car!" was never more true than the Buick GS 455, especially with the Stage 1 package.