SEI SE121 Upper Unit for MerCruiser Bravo One, Two & ThreeThe SEI SE121 is an aftermarket replacement upper unit for select MerCruiser Bravo One, Bravo Two, and Bravo Three sterndrives. Rated for applications up to 425 HP, it is available in three upper gear tooth counts to match your drive configuration.This item is subject to a 20% restocking fee.Year, serial number, and horsepower are required to process your order. Please contact us with this information after placing your order. Processing will be delayed until this information is received.Gear Selection and FitmentThe ratios below refer to the overall drive ratio for each Bravo application. Select the upper gear tooth count that matches your drive model and lower unit.Upper Gear Tooth CountBravo One RatioBravo Two RatioBravo Three Ratio29/271.36:11.50:1 or 1.81:11.36:1 or 1.81:130/231.65:12.20:12.20:1 or 2.43:132/271.50:11.65:1 or 2.00:11.50:1, 1.65:1, or 2.00:1Compatibility Requirements Uses the newer-style case with the oil recirculation passage toward the front.; Requires a lower unit with the matching oil passage; SEI specifies serial number 0F730000 and above.; Rated for applications up to 425 HP.; Does not replace Bravo X, XR, or XZ drives.; Confirm the drive model, overall ratio, and lower unit oil passage before ordering.OEM Replacement References 29/27 SEI 90-121-01C: 1589-8868H87; 30/23 SEI 90-121-01A: 1589-8868H88; 32/27 SEI 90-121-01B: 1589-8868H89; Not IncludedInstallation kit and anode kit are sold separately. This listing is for the upper unit only.