Initial design work on the GMC motorhome began in 1970 with an anticipated release date of 1973. The chief element was a front wheel drive design based on the successful Oldsmobile Toronado automobile, which incorporated a 455-cubic inch gasoline engine coupled with a Turbohydramatic 425 transmission with torsion bar suspension. The rear suspension utilized dual swing arms (one leading and one trailing) with a single air spring on each side.
The combination of the front wheel drive, which eliminated a bulky drive train to the rear, and the suspension elements allowed for a low-slung vehicle with car-like handling and ride. A ladder chassis topped with an aluminum frame sheathed with aluminum and molded fiberglass body panels resulted in a ground-hugging vehicle that avoided the stability and handling problems of top-heavy motorhomes. The molded fiberglass also allowed for a more streamlined design— a breath of fresh air during a time when motorhomes were becoming boxier every year.
The GMC motorhome debuted in May 1972 at the Transpro ‘72 trade show in Washington, D.C. The 1973 model year vehicles rolled off the assembly line a few months later to general acclaim from the recreational vehicle community. Two models were offered: Model 230 (23 feet) and Model 260 (26 feet). The coaches were available with a GMC-finished interior. The company also sold a Transmode configuration, which was a bare coach, to other RV manufacturers such as Avion and Coachman, who added their own interiors.
Like all motorhome manufacturers, GMC was hit hard by the 1973 energy crisis, although it was a large company with sufficient resources to weather the storm. But, eventually GMC officials determined that their factory space would be better utilized building small trucks, and in November 1977 an announcement was made that 1978 would be the last model year.
In the six years of production, approximately 13,000 units rolled off the assembly line, of which about 8,000 to 9,000 are still registered. Much of the endurance of the GMC can be traced to a legion of enthusiastic owners, the continued publication of the GMC Motorhome News and GMC Motorhome Marketplace, and the availability of parts from Cinnabar Engineering, which purchased all the motorhome property from GM and negotiated a license to provide OEM parts for the vehicles.
This 26-foot 1977 GMC Palm Beach model powered by an Olds 455 engine is owned by Richard and Jean Palmer. It was custom painted by Topeka Graphics of Topeka, Indiana, and photographed at Camp Dearborn, Michigan.
Douglas Keister’s new book, Mobile Mansions, will be published by Gibbs Smith Publisher in the spring of 2006. If you have a unique motorhome, e-mail a photo to firstname.lastname@example.org. Doug is also the author of Ready to Roll: A Celebration of the Classic American Travel Trailer and Silver Palaces: America’s Streamline Trailers. Personalized autographed copies are available from Doug. You can reach him at the e-mail address above.