BBM Shaft Rocker Arm Kit 1.70/1.70 Ratio

The T and D Machine BBM Shaft Rocker Arm Kit with 1.70/1.70 ratio is a precision cylinder head component engineered for marine engines requiring high-performance valve actuation. Built for serious boaters and marine technicians who demand reliable power delivery and consistent performance on the water, this rocker arm kit replaces worn or stock components that directly affect engine efficiency and responsiveness. Whether you're running a performance build or restoring a classic marine powerplant, the correct rocker arm ratio ensures your engine achieves optimal valve timing and lift characteristics.

The 1.70/1.70 ratio design amplifies camshaft lift by a factor of 1.70, translating smaller cam movement into precise, consistent valve opening across intake and exhaust ports. This balanced ratio delivers predictable mechanical advantage without over-stressing valve train components—critical when you're pushing an engine hard during extended throttle runs or rough water conditions. T and D Machine's BBM shaft platform uses durable materials and precision machining to minimize deflection under load, ensuring repeatability across multiple ignition cycles and maintaining the integrity of your fuel and ignition curves.

This kit is ideal for marine builders and experienced boaters upgrading engines that use BBM shaft architecture, particularly those seeking to maximize mid-range torque and top-end responsiveness without sacrificing durability. The 20-pound assembly requires proper installation on a prepared cylinder head with correctly set pushrod lengths and valve clearances—work best handled by a qualified marine engine technician familiar with your specific block and head combination. Proper rocker arm geometry is essential to avoid binding, excess wear, and valve float, making accurate setup and verification non-negotiable before launch.