S&S Cycle Super Stock Alternator Style Crankcase - Natural - 3.625in. Bore 31-0004Cast from A356 T 6 heat treated aluminum alloy Cases are available for 3 1 2in. stock and 3 5 8in. big bore motors for any stroke up to and including 5in. and most stock length connecting rods Machined to accept an oil filter assembly that mounts on the front of stock motor cases All races are line honed and breather cavity is precision machined to optimize breather timing for maximum oil scavenging Additional parts include crankcase bolts, washers