Oldsmobile, Buick and Pontiac 455: Are they all the same engine? – Jalopnik

For many gear beacon, the year 1970 represents the peak of the Muscle Car era -or at least the peak of the first Muscle Car era. A large part of what consumed to make 1970 special is that to remain competitive against brands such as Chrysler with his 440 Magnum, 440 Six Pack and 426 Hemi, General Motors are 400 Cubuse-inch size limit for motorcycles on which GM’s Muscle Cars were based.

Perhaps the most famous, this control change Chevy’s 454 cubic inch Chevelle SS in two flavors: a 360 hp LS5 or the ground pound LS6 with 450 hp. Parine than later these Big blocks with high compression would be impeded by performance-killing events such as an oil crisis, lead-free fuel, enveloping insurance rates and primitive emission controls, but it was glorious as long as it lasted.

Not to be surpassed, Oldsmobile, Buick and Pontiac have all raised the Ante from 400 to 455 cubic inch for their Cutlass 442, Gran Sport and GTO muscle cars, respectively. Given the modern practice of using “business” engines in multiple sub -brands, it could be assumed that these three 455 power plants are the same, but that is not the case. All three engines were developed independently, without shared architecture between them next to the event of achieving the same magical travel number. Moreover, each arrives at its 455 cubes via a unique bore and stroke measurement.

Oldsmobile, the company founded by Randsom Olds in 1897, released his second generation Pushrod V8 engine design in 1964 with a relocation of 330 cubic inches. Within a few years that design was expanded to the 455. Oldsmobile reached his 455 cubic centimeter by increasing the battle that a piston travels in his cylinder-versus the smaller 425 cube-inch iteration. The resulting longer deck height made the Olds 455 a really large block, with a 4.125-inch boring and the aforementioned 4,250-inch stroke.

This engine was available in large vehicles such as Sedans in Ware Size, Station wagons and Limited-Edition Hurst Muscle Cars already in 1968, but enthusiasts will remember the variant best in the 442 based on Cutlass-based 442 (shortly before four Vatencarb, four-speed package. That combination made 370 hp and a stumping 500 lb-ft torque. Interesting is that the thick 455 with its wide intake manifold also appeared in the Oldsmobile Toronado, an early GM car for the front-wheel drive.

The same “Unitized Power Package” that the FWD-Tornado attracted would also find an unlikely home in the futuristic GMC camper, the only motorhome produced by the factory ever offered by the big three of Detroit. If the Olds 455 has an Achilles heel, it is certainly the small oil returns, which starve the engine to oil at a high speed. Although it is good for driving on the street, this error gave the Olds 455 something of a bad reputation for use in drag racing and other High-RPM Motorsport, unless specially changed.

Just like Buick’s TurboLader, Intercooled Grand National and inconspicuous Regal T-Type in the 1980s, the Gran Sport Muscle Car of the brand was something of a sleeper. Buick is perhaps a name that is usually associated with pension communities and golf courses, but the 455-driven Gran Sport and GSX of 1970 were real Hell Raisers, albeit in a stylish outer wrapper. Buick’s version of the 455 has its roots in the new and 430 cubic inch engines in the new for 1967. In contrast to the 455s of some other GM brands, Buick chose to give his biggest relocation engine a large bore of 4,3125 inches instead of raising the battle, which remained at 3.90 inches.

Buick’s 455 certainly caused his share of boring land yachts, but the brand also released a specially coordinated “Stage 1” option that was available in his 1970 Muscle Cars such as the Gran Sport. In particular, Stadium 1 455 had a higher compression ratio, performance cam and larger valves. The result was 360 hp and 510 LB-FT torque. At a time when other manufacturers were susceptible to exaggerating the horsepower of their motorcycle to impress consumers, it was thought that the phase 1 Buick 455 was underestimated from the factory. In January 1970, Motor Trend got a 13.38 second pass in the standing quarter miles with a manual phase 1 of four gears. Although this is nothing special according to modern standards, the magazine the GS crowned the “fastest muscle car it has ever tested”, as reported by Haagerty.

Pontiac’s first trip to the empire of Pushrod V8 engines was far back in 1955 with a modest 287 cubic inch mill. It is remarkable that the same engine would change over the years in the Koppel-Sonster 455 of the brand. That means that, unlike the other brands in this article, it is not technically a large block. Pontiac’s Check on the 455 has a 4,1525-inch boring, 4.21-inch stroke, and was available with two-bolt or four-bolt main loddings, with the latest “High Output” (HO).

When even HO is not strong enough, buyers could opt for the superproof variation of the 455 with a processed motorcycle room with extra material added for strength, plus forged pistons and connecting bars. In 1970, Pontiac made 4,146 GTO muscle cars with the upper dog 455 cubic inch power plant, which made 360 ​​hp and 500 LB-FT torque. Although that is certainly respectable, it is worth mentioning that little to no power was won versus the smaller 400 cubic inch mill despite the extra 55 cubes, so what happened? The 400 Cube V8 had available RAM Air III and RAM Air IV equipment, including better breathable cylinder heads.

The 455 of 1970 would also receive the RAM-air treatment, but Pontiac deteriorated at the last minute, and quoted correctly upcoming fuel consumption and emission rules as a deal murderer. In the last production year, Pontiac’s 455 only made 200 hp in the screaming chicken decorated 1976 Transam. Yet that was enough to make it one of the fastest cars on the market in an America from the malaise era.