Two key characteristics differentiate stroker kits from OEM rotating assemblies.
First, and most important, the crankshaft's rod journals are physically farther from the main journals than on the original equipment. A given extension in the distance between the rod and main journals results in twice that distance in increase of piston travel. For example, in a Chrysler LA (1971-1992) 360 cubic inch (5.9 l) V8, the rod journal centerline is 1.79 in (4.55 cm) from the main journal centerline. The piston travels 3.58 in (9.1 cm) in this configuration. When this engine is modified with a 402 cubic inch (6.6 l) stroker kit, the distance between the main journal centerline and the rod journal centerline is increased to 2.00 in (5.08 cm), which results in the piston travelling 4.00 in (10.16 cm). So, the modified crankshaft with 0.21 in (0.53 cm) further distance between the main and rod journals results in 42 cubic inches (.7 ) of displacement greater than the engine had before.
The second key characteristic of a stroker kit versus OEM is the required changes to allow a stroked crank to 'fit'. This is accomplished in one of three ways:
▪ Location of the piston pin (and the top of the rod) within the piston, or the compression height is shortened.
▪ Length of the rod is shortened.
▪ Height of the cylinder is lengthened.
Stroker kit - Wikipedia, the free encyclopedia