HowStuffWorks advises that NASCAR engines cost $45,000 to $80,000 to build. Most of the top racing teams construct their own engines from scratch, and it takes engineers more than 100 hours of combined work to construct each Sprint Cup engine.
To meet specifications, engines must be no larger than 358 cubic inches. Such engines often produce upwards of 750 horsepower without turbo or superchargers. The intake and exhaust are specially designed to provide a boost at certain engine speeds. The carburetors of the engines are designed to take in large amounts of air and fuel for maximum performance, and with high-intensity programmable ignition systems, the spark timing is customized to provide maximum power.