Manufactured in 23 and 26 ft (7.0 and 7.9 m) lengths, the design was noted for its front-wheel drive and its low profile, fully integrated body.
Three or four of these 1/8 scale clay models were made, each with unique design characteristics, each refining their shapes closer to the final form.
Once these models were completed, evaluated, and approved, full-sized drawings were made using 1/4 inch tape to outline the front, rear and side design.
(At the time, the Buick Riviera, which shared most of the same components, and used the same E-body platform, as the Toronado and Eldorado until its 1977 downsizing, was still using the conventional rear-wheel-drive layout.)
The front-drive configuration eliminated the driveshaft and rear differential and the solid axle found on most front-engined motorhomes.
The rear bogies are suspended using a double-ended reversible sleeve airbag that is pressurized by an automatic leveling system to maintain the designed ride height.
The overall chassis design, from the use of an existing GM E platform powertrain and a modified rear suspension, has been considered an early ancestor of the crossover.
All GMC Motorhomes are 96 inches (240 cm) wide and about 9 feet (2.7 m) tall including the usually-installed roof air conditioner.
A press release datelined Pontiac, November 11, 1977, read as follows: “GMC Truck & Coach Division of General Motors plans to discontinue producing luxury MotorHomes and similar TransMode multi-purpose vehicles and convert those plant facilities to expand truck operations, a GM vice president said today.
Robert W. Truxell, general manager of GMC Truck & Coach said, “As a result of this action, GMC will be able to utilize production facilities more effectively for servicing growing truck demands.”[3] Another factor is that the driveline for the new 1979 E platform which was in the process of being downsized (and on which Buick would debut its first-ever front-wheel-drive Riviera) was lighter duty and incompatible with the GVW of the GMC motorhome where the existing Oldsmobile-sourced driveline was being phased out of production (the 403 and THM425 transaxle were phased out and replaced with the Oldsmobile 350 and THM325 when the downsized E platform was under development.)
[4] These included the Cortez Motor Home from the Clark Equipment Corporation which initially offered a four-speed manual transmission with front-wheel drive, available from 1963 to 1970 until the division was sold to Kent Industries.
[5] From 1972 to 1977, a redesigned Cortez-SD was manufactured, initially by Kent and later a group of investors, using the same Oldsmobile 455 and three-speed automatic transmission that the GMC motorhome adopted in 1973.
[6] Beginning in 1978, the Revcon took on a more aerodynamic design similar to the just-canceled GMC Motor home, which included a slant nose and dual rear axle, while adopting a Chevrolet 454 engine and Turbo-Hydramatic 475 transmission.