A stroker engine has an increased piston stroke over the factory engine, which leads to more displacement and subsequently more torque. This is achieved by increasing the throw of the crankshaft, increasing the length of the connecting rod, and decreasing the compression height of the piston.
An engine's stroke is the linear distance the piston travels when going from its lowest position to its highest position. Stroker kits are available for most small-block motors. They include all the necessary internal parts to convert a factory motor to a stroker motor. The parts in the kits are balanced, pre-assembled and checked for clearance before installation because when stroking a motor, it is common for the increased rod length and crankshaft throw to cause interference between parts.