Perfect for stock replacement and high performance applications in 1984-' 91 Harley-Davidson® big twin models. This 3-1/2" (stock) bore crankcase offers some unique features. Besides being machined for a crank position sensor, they are also compatible with stock flywheel assemblies, primary covers, gearcovers, and are clearanced for 38 amp alternator stators. Includes all required hardware, fittings, and bearings, natural aluminum finish.