The stock bore crankcase is machined with a rear motor mount similar to that of an Evolution® big twin engine, and will bolt directly into stock or aftermarket frames for 1984–'99 big twins. This type of crankcase uses the 1984–'99 style sprocket shaft seal, seal spacer, and alternator stator coil since it is intended to bolt up to the existing primary drive system of motorcycles of that year group.
- Greater overall strength than stock crankcases, especially in the front motor mount, an important consideration in high performance applications.
- All S&S crankcases use strong, dependable Timken® style sprocket shaft bearings to stand up to the most demanding applications.
- Clearanced for strokes up to and including 5".
- All passages between the crankcase cam support plate are o-ring sealed.
- Compatible with most stock components.
- Cam chest has clearance for up to .675" lift cams.
- Includes the S&S crankcase breather reed valve for Twin Cam 88® engines designed to eliminate oil carry-over and oil scavenging problems.
- Oil line installation kit PN 31-0424 is required for installation in 1999–'05 Dyna® models. This kit includes a special transmission top cover and oil lines.
- Oil line installation kit PN 31-0425 is required for installation in 2000–' 06 FLT models. Stock transmission top cover may be used.