Five essential calculators and converters for the serious enthusiast. Each tool is based on original factory specifications and engineering formulas.
Convert bias-ply sizes (e.g., 5.60-15, 6.70-15) to modern radial equivalents. Get overall diameter, section width, and speedometer error.
Open Tool →Baseline air-fuel ratio adjustment for altitude, air temperature, and engine displacement. Useful for Weber, SU, Stromberg, Holley.
Open Tool →Calculate engine RPM at any speed for each gear. Input transmission ratios, final drive, tire diameter. Perfect for rear-end swaps.
Open Tool →Compute static compression ratio for engine builds. Includes common vintage engine presets (small block Chevy, Ford, etc.).
Open Tool →Find NGK, Champion, Bosch, Denso equivalents for your vintage engine. Database includes 200+ common classic car/cycle plugs.
Open Tool →