”late” 91-09 conical style. Note: The 86-03/10-up style is preferred by many for better flow characteristics. Note: The 91-09 late style is a conical (tapered) shaped gasket that was introduced by The Factory in 1991 and replaced; again; with the early style in 2010. Note that the early style will fit all models and is generally seen as the better gasket design.