Mercury Mercruiser - Transom Assembly - Bravo - Magnum - Seacore - Used with SeaCore 4.3L, 5.0L, 350, & 377 Non-DTS Engines - 6-6911002TPBravo, Magnum Seacore Used with SeaCore 4. 3L, 5. 0L, 350, & 377 non DTS engines The transom assembly is the least discussed component but inarguably, one of the most important. This holds true for every MerCruiser sterndrive application. Most people's repower focus is on the engine and sterndrive. However, the transom delivers the cooling water, manages the exhaust, serves as the primary engine mount, controls the steering, manages the trim system,