S&S Cycle #31-0055 - Engine Case - Super Stock® - 3.500" - Evolution Big Twin

Perfect for stock replacement and high performance applications, these crankcases offer 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.

Features and Benefits:
Relocated cam chest oil pick-up increases gear case scavenging and virtually eliminates oil carry-over at sustained high speedsMachined to accept the stock oil filter assembly used on 1992–'99 big twinsA ported breather passageway and a machined breather window allows the air/oil mist to flow from the flywheel cavity to the cam chest of the engine with the least possible restrictionCrankcase venting can be achieved via two crankcase breathers, the cylinder heads, or both. We recommend using both crankcase breathers in engines larger than 95"Clearanced for strokes as long as 5"Compatible with stock 1984–'99 flywheel assemblies, primary covers, gearcovers, and clearanced for 38 amp alternator stators, making them perfect for stock replacement or high performance applicationsMachined for installation of a crank position sensor. This allows the cases to be used in stock EFI applications and also allows easy installation of S&S IST® Ignition and VFI Fuel Injection. A plug kit is included for applications that do not use a crank position sensor


Options
Available for stock, 3 5/8", and 3 13/16" bore applications with deck heights as much as 3/16" taller than stockNatural aluminum, black wrinkle powdercoat, and polished finish available






Crankcase Style
Finish

Part Number
Notes


3 1/2" Bore (Stock)
3 5/8"
Bore
3 5/8"
Bore
(Small Diameter)
3 13/16"
Bore


1992–'99
Natural
31-0005
31-0077
31-0073
31-0032
1, 3, 4


Black
31-0055
31-0078
31-0075
–


Polished

31-0079
–
–


NOTES: 1. 1992-'99 style oil pump. 2. 1984-'91 style oil pump. 3. Machined for 1984-'99 alloy primary. 4. Machined for stock or S&S EFI crank position sensor. Stock diameter only.











Note: All S&S crankcases manufactured after June 1, 2008 do not have case interlock groove and ring and do not use case alignment studs. Case mating surface is flat, and cases are aligned with alignment dowels.

Fitment