The copperhead (Agkistrodon contortrix) is a member of the pit viper family, like most of the venomous snakes in North America. The copperhead (Agkistrodon contortrix) is a member of the pit viper family, like most of the venomous snakes in North America.
The Command Thrust models use the same bigger gearcase housing as the Mercury 150 FourStroke, but with an all-new 2.38:1 ratio ideally suited for pontoons and heavier boats. Itâs the first true oversized gearcase in the industry for outboards in this horsepower range.
Unlike many modern engines, in which the camshaft rotates on top of the rocker arms to control the valves, the 351 instead features a single camshaft in the center of the engine block and a number of lifters and pushrods to actuate the valves. As the camshaft rotates, it pushes a lifter upwards.