COMP Cams Pushrod Top Xd-A

The COMP Cams XD-A pushrod top is the upper section of the XD-A adjustable pushrod system. COMP designed it to let engine builders set lash or lifter preload accurately while keeping non-adjustable-style rocker arms. This suits engines with low-mass rockers and a light valvetrain.

Key Features:

• Two-piece adjustable design. The top section slides about two inches inside a wider bottom section, with one or two shims captured between them.
• Shim-adjustable length. Adjustment runs over a range of 0.172 in. in 0.004 in. increments, using XD-A shims sold separately.
• 5/16 in. diameter top section, with a flat face that mates to the shims.
• Greater stiffness. The overlapping sections make a nearly solid area, and COMP reports a 90-percent increase in bending stiffness over a same-length 5/16 in., 0.105 in. wall pushrod. This helps valvetrain stability.
• Tested at over 9,000 RPM in solid roller LS applications.
• Top sections come in a range of lengths for coarse adjustment. They work with hydraulic and solid roller camshafts.

XD-A pushrods give builders a way to fine-tune pushrod length without changing rocker arms. They are a good fit for performance and racing valvetrain builds.