To build a hot rod chassis, you must first decide on the type of hot rod you wish to build. If building a pre-1940s car or truck, the chassis can usually be constructed using square tubing. On vehicles 1940 and newer, modifications to the original chassis must typically be made to create a hot rod chassis. Many aftermarket specialty companies manufacture and sell chassis components that will aid you in creating a hot rod chassis from scratch. With a plan laid out for the chassis, careful preparation and welding will ensure a straight and square chassis capable of supporting a high-horsepower drive line.
It is usually less expensive to buy an aftermarket frame kit than restoring an original frame. Once the type of hot rod has been decided upon, assembling the frame is the first step in the construction of a quality hot rod chassis. When the basic frame has been welded together, it is important to measure it to ensure it is straight and square. To accomplish this, take a measurement from a location on the right side of the frame at the front of the assembly and measure to a spot on the left rear. Record the measurement and then duplicate the measurement from the same locations on the other side of the frame.
The measurements should come out the same if the frame is square; if they do not, adjust the frame until they do. With a square frame constructed, the hot rod chassis can now be assembled. The front steering components are commonly assembled and fastened to the front axle first. There are many different types of front suspension to choose from when building a hot rod chassis. One of the most tried and true designs is a straight axle with leaf-type spring suspension; this suspension requires that the springs be affixed to the frame via spring shackles.
Once the springs are attached to the frame, the axle can be mounted to the springs with U-bolts. Next to be mounted are the steering components including the steering box. Most traditional style hot rods use a Vega or Corvair steering box due to their small size. Special mounting kits are available for either style. The shock absorbers are mounted next and connect to the axle and the frame to cushion the ride.
The next step in building a hot rod chassis is to install the rear axle. The rear axle also rides on leaf springs and installs in the same manner as the front axle. Once the rear shock absorbers are installed, the basic hot rod chassis is complete and ready for the drive line and body.
