Usage:
3500 Series Engines And 785 Trucks
Description of Change: New lifter assemblies are used in the valve mechanism groups on 3500 Series Engines and 785 Trucks. The body of the new lifter is .037 mm (.0015") smaller in diameter than the former lifter. Also, the tolerance of the roller pin bore perpendicularity has been tightened. These changes will help insure full surface contact between the camshaft lobe and the lifter roller. This will help increase the service life of the camshaft and lifter assembly.
Adaptable As: The new 7W8121 Lifter Assembly is a direct replacement for the former 2W3256 Lifter Assembly which is canceled. The 7N1858 Valve Mechanism group used on 3500 Series Engines and 785 Trucks has been changed to include the new 7W8121 Lifter Assembly.