Stock Bore Stroker Flywheel Kit 84''Upgrades 74'' and 80'' Shovelhead engines to 84'' displacement at approximately 8.4:1 or 7.3:1 compression (depending on pistons used)Includes a dynamically balanced 4-1/2'' stroke flywheel assembly complete with S&S heavy-duty connecting rods and mainshaftsReuse the stock cylinders, saving cost and retaining stock appearance of the engineMinor crankcase and cylinder modifications are required that can easily be done with hand toolsKit requires special pistons which must be ordered separately (Contact S&S for required pistons)