Rocker Arm Ratio - Power Multipliers

Rocker Arm Ratios Can Add Power

Mike Petralia Feb 1, 2002 0 Comment(s)
Sucp_0202_10_z Rocker_arm_ratio Comp_rockers 1/8

Time was short and we needed to test the full-roller rockers next. But instead of going with an aluminum rocker, we installed Comp's top-of-the-line Hi Tech stainless rockers with a 1.5 ratio.

More Ratio Also Means More Timing
As rocker ratio is increased, so, too, is valve timing. Note how changing from the stock ratio, which is actually closer to 1.46:1, to a true 1.60:1 will increase your total valve duration by almost 20 degrees! This geometric increase is true for any cam in any engine.

Rock On
The power our 383-cid Mouse gained just by bolting on a set of Comp Cams Magnum roller tip rocker arms made this whole thing worth the price of admission. The extra power and reduced heat and friction offered by the full roller Pro Magnum rockers in a 1.5:1 ratio also really makes them an attractive bolt-on.

Sucp_0202_11_z Rocker_arm_ratio Crower_rockers 2/8

Crower has developed a new rocker arm to cure many ailments, including the one we ran into. By relocating the hole in the rocker trunion (left), Crower eliminated the problem of pushrods hitting the heads. This also moves the rocker away from the retainer and can correct the problems associated with using longer valves and rotated valve angles.

Hot Rockers
The new kid on the block is definitely Hot Rockers from Everoc Industries. This unique system gives your engine the best of all rocker ratios automatically. By switching ratios as you drive, Hot Rockers gives great low-end grunt and fantastic economy along with a smooth transition to a high top-end ratio for more power. Hot Rockers have basically a full-roller, shaft-mounted design that offers stability and reduced friction at the valve tip, as well. We haven't had the chance to test Hot Rockers yet, but plan to do so soon. We'll let you know all about them in an upcoming story. Check out www.hotrocker.com to learn exactly how this ingenious system works.

Things To Check
Anytime you plan to increase the rocker arm ratio, there are several points to check.

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