This Impeller has the two flat sides that will only work on the newer style brass/bronze pumps that have 6 each 6mm x 16mm bolts holding the end cover on. NOTE: If you pump has 5 each of the 5/16" bolts, it will not work. Water Pump Impeller kit for Brass Sea Water Pump Housing includes the following items as well as a molded o-ring that creates a much easier installation into the groove. Replaces the following numbers: Mercuiser 47-862232A2 47-8M010422 Sierra 18-3016-1 GLM 89700 Includes Impeller Molded O-Ring that is much easier installation into groove Just drop in and go. Groove in brass pump is not symmetrical so seal will only fit one way. Replacement Kit fits the following: 2000 & Newer MCM V-6 & V-8 (305, 350 & 496 350 Mag., 4.3L, 496 Mag., 5.0L, 8.1S and MX 6.2L) With a Brass Sea Water Pump