The Billet Aluminum top cap is supported by eight bolts with a controlled water-circulation system and built in spray nozzles to provide maximum cooling to the external upper gear case.The steel tower in the floor is stabilized through internal lateral support beams to eliminate tower flex and gear deflection.IMCO has developed a rigid pinion and bearing pack assembly with non-elastic shims to provide the correct rolling torque while stabilizing both input yoke and pinion. Tightened to 75 lb/ft, the pinion assembly is held in place by our plated steel ujoint retainer nut through a direct load-bearing path.IMCO is the only manufacturer at this time that can offer four vertical lengths and three exterior finishes. See our lower section for more information.Our Xtreme Advantage SC drives are also available as upper units only, for those who may already own a IMCO, or a stock Bravo lower. Servicing can be performed by any qualified Mercruiser repair shop, no need to send back to the manufacturer. This means more time on the water.