This 4-1/8" wrinkle black S&S® stud pattern crankcase for 1999-'06 HD® Twin Cam 88®A engines (except 2006 HD® Dyna®) is much stronger than stock crankcases in every aspect. It has an extra large front motor mount for increased strength. The large cam chest allows cam lift up to .675" without clearancing, Timken® style sprocket shaft bearings withstand the most demanding applications. The S&S crankcase breather reed valve eliminates oil carry-over and oil scavenging problems. Clearanced for strokes up to 5". All passages between the crankcase and the cam support plate are o-ring sealed.