Different GM Body Platforms and What They Mean

GM X Body Style
General Motors X Body Style

General Motors uses letter codes to signify which chassis layout, or body type, the vehicle has. This is useful since GM consists of many different makes such as Chevrolet, Oldsmobile, Pontiac, Buick, and Cadillac. Many of these brands share platform types with each other. It isn’t some secret, alphabetic code that GM fans are privileged to. It is really quite simple. Each platform has changed somewhat over the years, so we’ll walk through them in more or less chronological order.

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The Early Years—A, B, C, and D Body

GM started with just four platforms: the A, B, C, and D bodies. In the beginning, the A body and B body were both for full-size cars.

GM A Body Models Included

  • Chevrolet Superior
  • Oldsmobile 60
  • Most Pontiacs

GM B Body Models Included

GM used the B body for the Buick Century, among others.

GM Discontinued the A Body for the B Body in 1959

GM decided it didn’t make sense to have two platforms for full-size cars, so they discontinued the A body, and made the B body the standard platform for full-sized cars in 1959.

GM continued to use the B body designation for full-size, rear-wheel drive cars until 1996. The Chevy Bel Air, Buick LeSabre, Chevy Impala, and Pontiac Bonneville were all built on the B body platform in this era.

GM Introduced the C Body in 1931

In 1931, GM Introduced the C body. The C body would continue as a long wheelbase RWD car until 1984. The C body was essentially a lengthened version of the B body. GM built the Pontiac Torpedo, Buick LaSalle, and Oldsmobile 90 on this platform.

The C body changed over to FWD in 1985, remaining a platform for full-sized cars. C body cars included the Cadillac DeVille, and Buick Electra and Park Avenue. GM built these C bodies until 1996.

GM Introduced the D Body in 1936

The D body was used from 1936 to 1996 for GM’s biggest cars, like the Cadillac Fleetwood Limo and the Buick Limited.

When the C body changed to FWD, some models previously built on the C body remained RWD. GM moved these models, like the Cadillac Fleetwood and Brougham, to the D body.

Branching Out—E, F, J, G, H, K, N, S, T, V, X, Y, and Z Body

GM Introduced the Z Body in 1960

In 1960, Chevy introduced a car different from anything else in GM’s lineup at the time. The Corvair was a rear-engined, compact car. Obviously, the chassis was quite different from other GM cars. So, from 1960-1969, the Corvair and its variants had their own platform as the Z-body.

In 1991, GM’s newly created subsidiary, Saturn, released its first cars, the S-series compacts. GM designated these as Z bodies. GM built the Saturn Z bodies from 1991-2002.

GM Introduced the Y Body in 1961

GM introduced another new platform, the Y body, in 1961. Gm used the Y body for compacts like Oldsmobile Cutlass, Pontiac Tempest, and Buick Skylark. They phased the Y body in 1963 after existing for only a couple years.

Chevy also introduced the fourth generation of the Corvette in 1984. Unlike previous Corvettes which had unique body-on-frame construction, the new one was designated as the Y body. GM still builds Corvettes on the Y platform today. From 2004-2009, GM also built the Cadillac XLR roadster on the Y body.

GM Introduced the X Body in 1962

In 1962, GM introduced another platform for compact cars, the X body. The the Chevy II used the X body early on. Similarly to what happened with the A and B bodies, GM had duplicate platforms with the X and Y bodies. The X body would continue as GM’s main compact platform until 1979. GM used the X body for the Chevy Nova, 1970s Buick Apollo, Oldsmobile Omega, and the Pontiac Ventura.

The X body was the next platform to join the K as FWD in 1980. GM used the platform for compacts like the Buick Skylark and Chevy Citation from 1980 to 1985.

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GM Introduced the E Body in 1963

The E body followed the X body in 1963. The E body was used for Personal luxury cars like the Buick Riviera, Oldsmobile Toronado and Cadillac Eldorado. Strangely, some early E bodies, like the Tornado, were front-wheel drive, and some, like the Riviera, were rear-wheel drive. FWD E bodies were the first front-wheel drive cars produced in the United States since 1937. By 1979, E bodies were all FWD. They continued in this configuration until 2002. This began GM’s slow shift toward focusing on FWD cars.

1979 saw many of GM’s older rear-wheel drive platforms start to change over to newer front-wheel drive platforms. By this point all E bodies were FWD.

GM Relaunched the A Body in 1964

The A body, absent since 1959, made a return in 1964. GM decided to re-use the A body name for its midsize cars like the Chevy Chevelle, and the Pontiac Tempest. The A body continued as a RWD platform until 1981.

In 1982, the FWD version of the A body was introduced. It was a stretched version of the X body and was used for midsized models like the Chevy Celebrity and Buick Century from 1982 to 1995.

GM Introduced the V Body in 1966

GM’s European subsidiary, Opel, developed another RWD platform, the V body in 1966. GM used it for various European and Australian market products from 1966 until 2006. They imported some of these models to the US in the late ‘90s and early 2000s as the Cadillac Catera, Chevy Caprice and Lumina, and the Pontiac GTO.

From 1987 to 1993, GM built the Cadillac Allante, a high end luxury car. GM designated the Allante as the V body, even though that name was already in use for unrelated international models.

GM Introduced the F Body in 1967

The F body might just be GM’s most famous platform. From 1967 to 2002, GM used the F body exclusively for the Chevy Camaro and the Pontiac Firebird and Trans Am. The F body was based on, and shared many parts with, the X body.

GM Introduced the G Body in 1969

GM briefly built the midsized luxury coupes, like the Chevy Monte Carlo and Pontiac Grand Prix, on the G body platform from 1969-1972.

When the A body became FWD, some models associated with the platform remained rear wheel drive. GM renamed these the G body and included the Buick Regal, Chevy El Camino, and Pontiac Bonneville. GM built these RWD G bodies from 1982-1988.

GM introduced a new G body platform, in 1995, to replace its several, existing large car platforms. As it did with the A and B bodies in the 1950s, GM had once again found itself with overlapping platforms. In the following decades it moved toward consolidating these over lapping platforms into new ones. The new G body was based on the K body used by Cadillac. It replaced the previous G body, as well as the K body, C body, and H body. Confusingly, models previously based on those platforms continued to use their old platform names in marketing materials, and in their VINs, even though they were being built on the new G body platform. The G body continued until 2011 in the form of the Cadillac DTS and Buick Lucerne.

GM Introduced the H Body in 1971

As cars tended to grow smaller in the 1970s, GM introduced its first platform for subcompact cars. From 1971 to 1980 GM used the H body for subcompact cars like the Chevy Monza, Buick Skyhawk, and Pontiac Starfire.

In 1986, GM reintroduced the H body name. While the original H body was for RWD compact cars, the new one was used for FWD, full-size cars like the Buick LeSabre and Pontiac Bonneville. GM previously built many of these models on the B body. The H body shared some parts in common with the C, G, and K bodies. GM built it until 1999.

GM Introduced the T Body in 1973

GM had another subcompact platform, the T body, used from 1973 to 1978. This platform was used internationally for the Isuzu Impulse, and domestically for the Chevy Chevette.

GM also introduced the FWD T body for the international market. T bodies are still being sold overseas, but the 1988-1993 Pontiac LeMans was the only FWD T body sold in the US.

GM Introduced the K Body in 1975

The K platform was a stretched version of the X platform. GM used it for the Cadillac Seville from 1975 to 1979.

In 1980, the K body changed to FWD, where it was still used to build Sevilles. This K body was very similar to the E body. GM used the K body for sedans and the E body for coupes.

GM Introduced the J Body in 1981

While other platforms were changed to front wheel drive versions, GM outright replaced the H body in 1981 with its FWD counterpart the J body. The J Body was meant to reduce engineering expenses for GM’s entry level models, by providing a shared platform across brands. It’s the only platform that had one model from each of GM’s five main brands: the Cadillac Cimaron, Oldsmobile Firenze, Buick Skyhawk, Chevy Cavalier, and the Pontiac J2000. GM used the J body for the Pontiac Sunbird from 1985 to 1994 and the Sunfire from 1995 to 2005.

GM Introduced the S Body in 1983

In 1983, GM struck a deal with Suzuki to import its supermini Suzuki Swift. GM sold the Swift, as well as its own rebadged versions, the Geo Metro and Chevy Sprint from 1983 to 2003. It designated these as the S body.

GM Introduced the P Body in 1984

In 1984, Pontiac released the Fiero. Like the Corvair, the Fiero had its engine mounted behind the driver. Also like the Corvair, it differed from GM’s other offerings so much that it merited its own platform: the P Body. GM built Fieros on the P body until 1988.

From 1985 to 1992, GM brought in more rebadged Suzuki vehicles, like the Chevy Spectrum, Geo Storm, and Isuzu Impulse. Confusingly these were designated as the P body, even though that name was still in use for the unrelated Fiero’s platform.

From 1996-1999, GM briefly leased an electric car called the EV1. General Motors designated it as the P body. GM considered the EV1 lessees participants in an engineering evaluation. GM repossessed and destroyed most EV1s at the end of the lease period, and donated a handful to museums.

GM Introduced the N Body in 1984

The N body replaced the X body as GM’s platform for compact cars in 1985. Oldsmobile originally engineered it and GM placed it on the Oldsmobile Calais, Pontiac Grand Am, and Buick Skylark until 1998.

GM Introduced the L Body in 1984

The L body joined the N body as another platform for compact cars in 1987. While Oldsmobile engineers developed the N body, Chevy engineers developed the L body. GM eventually used it for the Chevy Beretta and Corsica, until 1996.

GM Introduced the M Body in 1985

The M Body replaced the S body in 1985, when GM introduced the next generation of the Suzuki Swift and Geo Metro. GM built M bodies until 1994.

GM Introduced the W Body in 1988

GM introduced a new midsize car platform, the W body in 1988. It was used for models like the Buick Regal and Chevy Lumina, and is in use today for the Chevy Impala.

New Nomenclature—GMX130, Sigma, Delta, Epsilon, Zeta, Kappa, Alpha Body

GM Introduced the GMX130 Body in 1998

In 1998, GM introduced a new platform to replace the N, A, and L bodies, and continued GMs simplifying of its line. Breaking with the alphabetic naming scheme, they named it the GMX130 platform and used it for the Oldsmobile Alero and Chevy Classic, among others, until 2005.

GM Introduced the Sigma Body in 2002

As GM moved into the 21st century, it started using Greek letters to designate its new platforms. The first of these was the Sigma platform in 2002. The Sigma platform is GM’s midsized, rear wheel drive platform. Cadillac used it for the CTS until 2013, and for the STS. It replaced the V body Cadillac Catera.

GM Introduced the Delta Body in 2003

The Delta platform replaced the T, J, and Z platforms as the basis for compact cars and crossovers. GM has used it since 2003 for models like the Chevy Cobalt and Cruze, Pontiac G5, and Saturn Ion. It is still in use.

GM Introduced the Epsilon Body in 2003

GM also introduced the Epsilon platform in 2003. GM uses it for midsize FWD cars, like the Saab 9-5, Saturn Aura, Chevy Malibu, and the Cadillac XTS.

GM Introduced the Zeta Body in 2006

In 2006, GM’s Australian subsidiary, Holden, developed the Zeta platform, as a replacement for the V body. The Zeta platform is sometimes called the “Global RWD Architecture.” Many Holden models are based on it, as well as the Pontiac G8, and the Chevy SS. GM also used it for the fifth generation Chevy Camaro, which makes the Zeta platform the successor to the F body as well as the V body.

GM Introduced the Kappa Body in 2006

2006 also saw the release of a pair of roadsters from Pontiac and Saturn, the Solstice and Sky, respectively. GM built these on the Kappa platform. The Kappa platform did not live for long, only lasting until 2009.

GM Introduced the Alpha Body in 2012

The Alpha platform is GM’s most recently developed platform. Released in 2012, it is used by Cadillac for the ATS, and for the CTS since 2014.


If you’ve made it this far, congratulations. You now know all about GM’s different body platforms. Admittedly, this subject can get pretty complicated at points. You can see why GM’s recent trend has been to consolidate its platforms. That thankfully streamlines their product lines, which was the whole point of sharing these platforms in the first place.

Written by Dan Smolinsky.

11 thoughts to “Different GM Body Platforms and What They Mean”

  1. i read all that you wrote, I seen nothing on the catalina.. I have a 1965 catalina sport coupe ( 2 door). What type of frame do I have and what other cars of that year or any year parts are compatable. I am wanting to put all disc brakes on but having no luck at all in finding anything that are interchangeable with it..

    Thanks Scott

    1. I hate to sound rude about this but I just can’t imagine how you couldn’t find the answer to that simply because it isn’t stated in this article. If you just Google Pontiac Catalina it tells you right there first thing in huge bold letters. “GM B Platform”. If you have a classic car like that which you plan on doing any kind of work on, your gonna have to do plenty of research on that car and various car systems in general. How this works, how that works and so on… The good news is the internet is just chock full of information. For really technical information on very specific stuff your best bet is signing up for at least one online forum like http://www.pontiacforum.com or something like that. You can ask specific questions on there that only die hard Pontiac guys would know and there will be dozens of people eager to help. They just live for this stuff. For more basic/general information kind of stuff youtube is great. Personally I like to learn visually. Let’s say you have a cracked fuel line that is leaking. You can go on YouTube and learn how to fix that leak with a compression fitting. It’s more or less the same exact procedure for any car regardless of make/model even foreign/domestic and it’s a rather simple job but one that the average person didn’t necessarily know how to do. On you youtube you can get 5 different takes from 5 different people each with their own unique techniques in a short time. Hope this helps in some way. Good luck!

  2. I see a minor error when discussing the X body of 1961. You refer to the Chevy Nova, Pontiac Ventura and Buick Skylark using that platform. The Buick was named the Omega, the Skylark was a bigger car being an intermediate.

    1. Omega was Oldsmobile, at least at the start of the 1970s.

      I don’t recall if there even was a Buick version, but you’re right that the Skylark wasn’t it.

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