This Shaft Mount Aluminum Roller Rocker Arm from COMP Cams is designed for Chrysler V8 383-440 Applications and has a 1.6 ratio. Mounted on an ultra-durable shaft, this Rocker arm is made from a high quality aluminum alloy with a tensile strength of 80,000 psi. Needle bearing trunnions allow valve spring pressures of up to 350 lbs. open pressure, making Aluminum Roller Rocker Arms a good choice for many street applications.