Availability
Roller rockers increase power through reduced friction and increased rigidity
Increasing rocker arm ratio increases valve lift without changing the...
Roller rockers increase power through reduced friction and increased rigidity
Increasing rocker arm ratio increases valve lift without changing the camshaft
Bolt-down rockers are common on GM LS and Ford engines
Shaft mount is common on Mopar and race engines
Stud mount is commonly used on Chevy and other GM engines and is the most popular style used in aftermarket cylinder heads
Summit Racing offers a variety of engine rocker arms designed for both high-performance and everyday vehicle applications. Our lineup includes options for GM, Ford, and AMC. Summit rockers are available as stamped steel stock replacement,...
Roller rockers increase power through reduced friction and increased rigidity
Increasing rocker arm ratio increases valve lift without changing the camshaft
Bolt-down rockers are common on GM LS and Ford engines
Shaft mount is common on Mopar and race engines
Stud mount is commonly used on Chevy and other GM engines and is the most popular style used in aftermarket cylinder heads
Summit Racing offers a variety of engine rocker arms designed for both high-performance and everyday vehicle applications. Our lineup includes options for GM, Ford, and AMC. Summit rockers are available as stamped steel stock replacement, full roller, with a bearing pivot and roller tip, and roller tip only that maintain the standard OE pivot ball or fulcrum. Full roller rockers are available in stainless steel and aluminum, and roller tip rockers are available in standard or chromoly steel.
Rocker arms are responsible for transmitting movement from the pushrods (actuated by the lifters following the camshaft lobes) to the engine valves. Rocker arms multiply camshaft lobe lift to create additional lift at the valve. Common rocker ratios range from 1.5 to 1.8. For instance, if a camshaft has a lobe lift of 0.300 inches and is paired with a rocker arm having a ratio of 1.5, the resulting valve lift will be 0.450 inches (calculated as 0.300 x 1.5 = 0.450). Similarly, a camshaft with the same 0.300-inch lobe lift used with a 1.6 ratio rocker will achieve a valve lift of 0.480 inches.
Changing the rocker ratios is a simple and less expensive way to increase valve lift without altering the camshaft's advertised duration. However, the ratio increase allows the valve to open more quickly from its seat, which can slightly extend the duration at .050-inch lift—an essential measurement point for comparing different camshaft grinds. When upgrading the rocker ratio, it is crucial to verify that the increased lift remains within the range of the valve spring and doesn’t create piston-to-valve interference issues.
Updating to roller rocker arms offers several benefits besides the possibility of increased valve lift, including reduced valvetrain friction, greater strength, and more power transferred due to less friction. Most stock rocker arms pivot on a metal-to-metal fulcrum or ball that has grooves to hold oil. This design is acceptable for stock engines and even mild performance applications. However, when using larger lift cams with more aggressive spring pressures, stock systems will be taxed beyond their limits. Roller rockers, on the other hand, pivot on a caged bearing or trunnion, which significantly reduces friction while effectively handling higher spring loads. The roller tip on rocker arms features a small roller wheel that contacts the top of the valve stem or lash cap, if used. This design helps reduce scuffing and side loading across the top of the valve during the lifting action; reducing friction and helping to preserve valve guides with high-lift cams.
Rockers generally use three types of mounting systems: bolt-down, shaft-mount, and stud mount.
Bolt-down options are common in Ford and GM LS applications. Bolt-down Ford rockers use a rocker arm channel that a fulcrum mounts in to align the rocker with the valve stem. LS rockers use rocker arm stands to align the rocker arm.
Shaft-mount rockers are common in Mopar and extreme performance applications where the rocker arms pivot on a shaft that runs the length of the cylinder head.
Stud-mount rockers ride on a rocker arm stud that’s threaded (or pressed in with most OE applications) into the cylinder head. Threaded versions are common with aftermarket head designs and require pushrod guideplates to align the rockers to the valve stems. The exception is self-aligning or rail type rockers, which have shoulders at the rocker arm tip that keep the rocker arm centered over the valve stem.
When upgrades are made to an engine, such as a cam change, cylinder head modification or replacement, or surface decking, it's common to require a unique length pushrod (usually within +/- .0500-.0200-inch of stock size) to maintain proper valve preload/lash and rocker arm geometry across the valve stem. Correct rocker arm geometry is when the tip of the rocker arm stays in contact with the center of the valve stem tip during the cycle of valve action. Pushrod length checkers are used to determine the correct length pushrod needed to maintain proper rocker arm geometry. To adjust hydraulic lifter preload on threaded rocker arms, you'll need to find the zero lash point, then add a specified amount of preload by tightening the adjuster nut on the rocker arm. Generally, bolt-down rocker arm systems have a fixed pivot point and are non-adjustable. To adjust lifter preload on bolt-down rockers (like on OE Ford applications), it’s common to use shims, mill the fulcrum, or slightly different length pushrods. When ordering rocker arms, pay attention to the maximum spring diameter listed to avoid interference issues.
A. Rocker arms, especially when upgraded to full roller rockers, can enhance horsepower, but the exact gains will vary. A swap to roller rockers may result in a modest increase of a few horsepower due to reduced friction. However, significant improvements—potentially 20 horsepower or more—can be realized by increasing the rocker arm ratio (for example, from 1.5 to 1.6) and optimizing valve lift, which in turn can improve engine breathing.
Q. What are the symptoms of a bad rocker arm?
A. A faulty rocker arm can lead to various symptoms, such as unusual engine noises like clicking or ticking, reduced engine power, and rough idling or stalling. You might also notice a decrease in fuel efficiency, experience misfires, or even engine backfires.
A. To check rocker arms, start with a visual inspection for wear, damage, bearing play (in roller applications) and adequate lubrication. Specifically, examine the rocker arm shaft bore, sockets, and lock nuts. Ensure that there is proper oil flow through the pushrods, and listen for any clicking or ticking noises that may indicate a problem.
A. Self-aligning or rail type rocker arms are designed to maintain proper alignment with the valve stem. They achieve this with a shoulder on the rocker pad or around the roller tip that surrounds or captures the valve stem, eliminating the need for pushrod guide plates. These rocker arms are commonly found on 1987-up center-bolt small block Chevy cylinder heads, and 1977 and earlier Ford Windsor based engines.
A. Determining the correct rocker arm geometry involves getting the proper length pushrod and making sure the rocker tip contacts the valve correctly. You will need a pushrod length checker and a way to mark the valve tip, such as a permanent marker. Adjust the pushrod length until the witness mark is centered on the valve tip while the engine is turned over through a complete valve cycle. This shows that the valvetrain geometry is correct. Using a solid lifter—or modifying an extra hydraulic lifter by removing the spring and adding washers or shims—is recommended to rule out false readings from hydraulic lifter collapse during this procedure.
Showing In Stock Items. Show All 72 Items.
Rocker Arms, Trunnion Upgrade, Assembled, Cast Steel, 1.7 Ratio, Straight Body, Cathedral Port, Chevy, LS1, LS2, LS6, LQ4, LQ9, Set of 16
Part Number: SUM-141556
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Roller Bearing Trunnion, L92/LS9/LS3, Assembled, Heavy Duty Cast Steel, 1.7 Ratio, Rectangle Port, Chevy, Set of 16
Part Number: SUM-141554
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, 1.5 Ratio, 3/8 in. Stud, Full Roller, Stainless Steel, Natural, Small Chevy, SBC, Set of 16
Part Number: SUM-G6990
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Roller Tip, Cast Steel, 3/8 in. Stud Mount, 1.5 Ratio, Polylocks, Chevy, Small Block, Set of 16
Part Number: SUM-141706PL
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, 1.7 Ratio, 7/16 in. Stud, Full Roller, Stainless Steel, Polished, Big Block Chevy, BBC, Set of 16
Part Number: SUM-G6995
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.6 Ratio, Fits 3/8 in. Stud, Ford, Small Block/351W, Set of 16
Part Number: SUM-G6940B
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.7 Ratio, Fits 7/16 in. Stud, Chevy, Big Block, Set of 16
Part Number: SUM-G6930B
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Roller Tip, Grooved Pivot Balls, Stamped Steel, 1.5 Ratio, Fits 3/8 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-141506
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.5 Ratio, Fits 3/8 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-G6905
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.5 Ratio, Fits 7/16 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-G6911B
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.5 Ratio, Fits 3/8 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-G6910B
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, 1.6 Ratio, 3/8 in. Stud, Full Roller, Stainless Steel, Polished, Small Chevy, SBC, Set of 16
Part Number: SUM-G6991
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Roller Tip, Cast Steel, 7/16 in. Stud Mount, 1.72 Ratio, Polylocks, Chevy, Ford, Set of 16
Part Number: SUM-141709PL
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, OEM-Style, Stamped Steel, 1.5 Ratio, Fits 3/8 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-G6800
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Roller Tip, Self-Aligning, Cast Steel, 3/8 in. Stud Mount, 1.5 Ratio, Polylocks, Chevy, Small Block, Set of 16
Part Number: SUM-141700PL
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Pedestal Mount, Full Roller, Aluminum, 1.7 Ratio, Chevy, LS, Set of 16
Part Number: SUM-G6980
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, 1.6 Ratio, 3/8 in. Stud, Full Roller, Stainless Steel, Polished, Small Block Ford, SBF, Set of 16
Part Number: SUM-G6996
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Roller Bearing Trunnion, LS-7, Assembled, Heavy Duty Cast Steel, 1.8 Ratio, Rectangle Port, Chevy, Set of 16
Part Number: SUM-141555
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, OEM-Style, Stamped Steel, 1.7 Ratio, Fits 7/16 in. Stud, Chevy, Big Block, Set of 16
Part Number: SUM-G6803
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Roller Tip, Self-Aligning, Cast Steel, 3/8 in. Stud Mount, 1.6 Ratio, Polylocks, Chevy, 305, 350, Set of 16
Part Number: SUM-141701PL
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.6 Ratio, Fits 7/16 in. Stud, Ford, Small Block/351W, Set of 16
Part Number: SUM-G6941B
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.6 Ratio, Fits 7/16 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-G6921B
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, OEM-Style, Stamped Steel, 1.6 Ratio, Fits 3/8 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-G6801
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Stud Mount, Full Roller, Aluminum, 1.6 Ratio, Fits 3/8 in. Stud, Chevy, Small Block, Set of 16
Part Number: SUM-G6920B
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
Rocker Arms, Roller Tip, Cast Steel, 3/8 in. Stud Mount, 1.6 Ratio, Polylocks, Chevy, Small Block, Set of 16
Part Number: SUM-141707PL
Estimated Ship Date: Friday 12/26/2025
Estimated Ship Date: Friday 12/26/2025
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