Replacement Twin Cam "A" engine cases for stock H-D chassis only (carb and EFI). Feature greater overall strength than stock crankcases. Strong, dependable Timken®-style sprocket shaft bearings. 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. Include S&S crankcase breather reed valve designed to eliminate oil carry-over and oil scavenging problems. Rear motor mount bolts directly to the stock transmission; fully compatible with the stock primary, charging system, and other stock components. Made in the U.S.A.. This project requires a skilled technician. It is the responsibility of the person assembling the parts to check all clearances and assembly specifications..