This manual covers the 1966 Plymouth Valiant, a versatile compact car offered in various models including the V-100, V-200, Signet, and Barracuda. Known for its robust engineering, the Valiant was a product of the Chrysler Corporation, available with a range of engines from the efficient Slant-Six to powerful V8 options. Its design and construction reflect the automotive standards of its era, emphasizing reliability and practicality for everyday use and as a platform for performance enthusiasts. The AP1 chassis code denotes this specific generation, which was manufactured in the United States. This comprehensive factory service manual provides detailed instructions for the full service, repair, and maintenance of the 1966 Plymouth Valiant. It covers all major systems, including engine diagnostics and overhaul for Slant-Six and V8 variants, manual and automatic transmissions, braking systems, suspension and steering, and the electrical system. The manual also details fuel, cooling, body, and HVAC systems, along with essential maintenance procedures such as oil changes and tune-ups, and troubleshooting guides for common issues. This resource is invaluable for DIY enthusiasts, classic car owners, and professional mechanics seeking to maintain and repair their vehicles accurately and efficiently.