Swamp buggies were first produced in the 1930s for exploring the wetlands of southern Florida, and according to the experts at Swamp Buggy Races, the earliest known versions were adapted from Ford Model A cars. Soon hunters and tour guides recognised such vehicles' potential to easily negotiate areas no other vehicles could even access, where no roads had ever existed, and to this day swamp buggies can cover terrain impossible for other purpose-built off-road four-wheel-drive vehicles. Building a swamp buggy is a complex project requiring much forethought and planning.
Learn how other swamp buggy builders structure their chassis, which are usually fabricated in two sections. The lower deck should accommodate the engine, transmission, axles, suspension and wheels, while the upper deck supports seats, driver controls and accessories, with a firewall between the two. Repurpose a truck shell, or construct a purpose-built frame from tubular steel or aluminium.
Decide what priorities the engine must answer. Although competition swamp buggies run 1000-horsepower V8s, many weekend enthusiasts use Jeep four-cylinder engines. With a great deal of gear reduction relatively small engines can develop a lot of torque, so a six cylinder or small-block V8 engine can be very workmanlike. If designing a swamp buggy for racing, replace as many engine components as possible with aluminium aftermarket parts to minimise weight.
Determine which transmission configuration will best suit your purposes. While some swamp buggies are fitted with automatic transmissions and four-by-four drive trains, three-speed manual gearboxes and two-by-four drive trains tend to outlast the alternatives in high-stress applications. They are also far easier to repair when they do fail. Use a hydraulic clutch to obviate all the work involved in fabricating a custom mechanical linkage.
Trade off axle weight against strength. Larger tires demand stronger axles, and the lighter the rest of the vehicle is kept the heavier the axles can be. Use front and rear axles salvaged from three-quarter-ton or greater trucks. Axle gearing ratios should be very low, in the range of 4.11; with this configuration even relatively small engines can generate extraordinary torque at the tire.
Plan on fully independent front and rear four-link suspension trains and heavy-duty shock absorbers fitted on three-inch suspension lift kits. According to the experts at Summit Racing, Edelbrock shocks are considered "The ultimate upgrade."
Choose 35-inch tires or greater for swamp buggies that have the same rim sizes on both axles. Some builders prefer 33-inch tires for the front and 37-inch on the rear; this is a more a matter of style than functionality. Manufacturers such as Baja make speciality "balloon tires" that can exceed five feet in height and cost over a thousand dollars each, but many sport swampers simply fit used tractor tires.
Opt for accessories that may become necessities when things go wrong far from assistance. Weld "D"-rings at several points around the body to attach come-alongs, obtain a high lift jack, store shovels, chains and straps in lockers bolted to the lower deck. Fit an electric winch, a CB radio, corner guards and heavy-duty bumpers.
Although less manoeuvrable, swamp buggies which run on tank tracks are even more capable over drier, heavily wooded terrain. Balloon tires allow the vehicle to float and move over water under its own propulsion, and this is a consideration in swamps where knee-deep water as dark as tea can suddenly plunge to depths of 12-feet or more. Swamp buggy chassis are seldom equipped with brakes, because the terrain they are intended to cover and the tread depths of their massive tires stop the vehicle almost immediately upon the engine powering off.