Direct Replacement Riser, OMC-20-982680. Replaces OMC# 982680 Fits OMC Small block Chevrolet w/ log style manifolds When choosing a Manifold, it is recommended to also choose the appropriate new risers / elbows. Although Manifolds such as Barr, Osco and others including original equipment often look alike, it is recommended to buy manifolds and risers as sets. Where applicable, buy replacement manifolds in pairs and be sure to include the appropriate riser / elbow. These steps will help ensure compatibility and reliable operation of your marine engines exhaust system for years to come.