Sierra 18-1908 MerCruiser V6/V8 3" Manifold Riser SpacerSize: 3"For: MerCruiser GM V6 229 and 262cu.in. (Models: 185 and 205); GM Small Block V8 305-350cu.in. (Models: 200, 228, 230, 260 and 898); GM Big Block V8 454cu.in. (Models: 330, 340 and 7.4L); Use With: Manifold: 18-1952-1, 18-1953-2, or 18-1957-1; Elbow: 18-1970-1,18-1976-1; Exhaust Elbow Mounting Kit: 18-8554,18-8554, and 18-8556; Exhaust Elbow Gasket: 18-0672, 18-0897, and 18-2849-1; Interchangeable With: Barr; MC-20-93320A3; MerCruiser; 93322; Mallory; 9-40530; Osco; 3320;