Stage Four begins our 4.1L Stroker kit, raising your horsepower from 1,300 to 1,500. Beginning with opening the engine to replace your factory crankshaft with our GT1R 94mm crank, replacing the prior rod choice with a 300mm Tri Beam from Manley coupled with their wrist pins and pistons. This package is for those who prefer more torque with the revs and more displacement served with their boost.