1.375-inch crank pilot. 26-spline input. 10.5-inch bolt circle. 3400-3800 RPM stall This Holeshot 3800 fits Ford C4 automatic transmissions with 26 spline input,1.375-inch crank pilot and 10.5-inch bolt circle. Holeshot torque converters are for serious-minded performance enthusiasts and offer additional strength and durability features not found in our Traveler or Tork Master series of converters. The Holeshot provides a higher than stock stall speed with several advantages and benefits for vehicles with modified engines, particularly big cams which tend to reduce low-end torque and drivability. The higher stall speed of this converter will launch the car in a higher rpm range where more torque is readily available, resulting in quicker acceleration. Holeshot converters feature furnace brazed impeller fins and turbine, new precision alloy impeller hub and new heavy duty needle bearings. Other features include fully balanced and pressure tested by expert technicians. If your vehicle is equipped with a plate type nitrous system or supercharger, please refer to the Nitrous Holeshot line of converters. Notes: Stall speed listings are based on engines producing 230lb. ft. of torque at 2,500 rpm. More torque at 2,500 rpm will give you more stall speed, less torque at 2,500 rpm will give you less stall speed than the stall speed ratings indicated. Higher stall converters can generate more heat, so we highly recommend adding a transmission cooler. This converter is Not recommended for supercharged, plate-type nitrous oxide or trans-brake applications. The product images shown are for illustration purposes only and may not be an exact representation of the product. Fits vehicles with Ford C-4 Automatic transmissions with 26 spline input,1.375-inch crank pilot and 10.5-inch bolt circle.