A street rod is a custom built vehicle designed for higher speeds and power than a factory built vehicle, and can take on many forms. Some are built from a standard every day factory vehicle, modifying the engine, transmission, suspension, and computer for increased acceleration, power, and handling. Other street rods are built from an antique vehicle. The chassis, interior, and even exterior are often completely redone for added aesthetic appeal, many times including customized design. A modern and more powerful engine will be installed, coupled with a specifically selected transmission with gears designed for certain traits such as higher torque and power, greater acceleration, or a higher top speed. A street rod is often built with a specific goal. Some are designed for higher top end speeds. These vehicles will be equipped with a transmission with higher gears, allowing the engine to propel the vehicle at high speeds and a relatively low RPM load on the engine. These vehicles will often have modifications done to the computer controls of the engine, including the governor and emissions regulator if necessary. The governor is a limiting device installed in factory cars to limit the power output and top speed of a vehicle. In everyday commuter cars, this is for the safety of the engine and also of the driver. However, this is something that would limit a street rod, and in many cases is modified or removed completely.
Other street rod vehicles are designed for quick acceleration. These are generally used in short heats or sprints. The vehicle will be have a transmission equipped with low gears, enabling more power output for a faster start and acceleration. The RPM capabilities will also be greater in the engine itself, as it will be run with a higher load on the engine. The computer in the vehicle will also be modified to allow for the increased pressure and speed in the internal components. The transmission will be designed for fast gear shifts with minimum power loss. The vehicle will also be equipped with tires and suspension components specifically designed for increased traction and grip on the road Besides power and performance, many street rods are also designed for aesthetic appeal. Some vehicles will be either lowered to ride closer to the ground, or lifted to look more like a monster truck or to allow larger tires to be installed. In this case, the aesthetic appeal is often linked to performance. A vehicle that is lowered will often be more aerodynamically suited, and will be capable of greater speeds. A lifted vehicle will allow for larger tires, which is another way of increasing certain gear ratios. The outer body of street rods will also very often be modified. Fenders may be modified allowing for narrower tires, or covered to show less of the wheels. A chop top vehicle will make the cab appear shorter for a greater streamlined effect. Hoods may be modified for increased airflow by installing hood scoops or modified grills. Customized head and tail lights may be used for a more dramatic effect.
Street rods are fully customized automobiles that are put together with different goals in mind. Many are made as personal projects by typical backyard mechanics. These individuals use their knowledge of automobiles to create their own dream vehicle. Others have the dream for a vehicle, but not the knowledge or desire to create it themselves. In this case, there are many specialty mechanics and shops who can be hired to create the perfect hot rod. Their knowledge and professional facilities will allow virtually any vehicle to be created. No matter where street rods originate from, the possibilities in auto design and capabilities are endless. Street rods are an automotive culture that allows unique and powerful vehicles to be created and enjoyed by many people.