Roller rockers make power two ways. First, a rollerized rocker fulcrum reduces energy losses from mechanical friction in the drivetrain, freeing up horsepower. At the same 6,000-rpm peak, we made 401.1 hp and 412.9 lb-ft of torque, a gain of 11.2 hp and 5.9 lb-ft of torque.
Do roller rockers improve performance?
For engine applications that demand a step up, replacing the stock stamped or cast steel rockers with aluminum roller rockers will typically produce a gain of 10 to 15 hp with the same lift ratio, and even more of a power gain with a higher lift ratio.
What ratio are stock rocker arms?
1.6:1 ratio
The rocker arm is the link between the camshaft and the valves – functioning as a lever arm to multiply the cams lobe lift to the valve lift. Stock rocker arm ratios vary between manufacturers and engine types, but generally all small block Fords come with a 1.6:1 ratio rocker arm.
What are the stock rocker arm ratio on a 302 Ford?
1.6:1
Remember, too, that the stock Chevy rocker-arm ratio is 1.5:1, compared with 1.6:1 for a stock Ford.
What size roller rockers do I need?
The ratio of a rocker arm refers to the amount of movement on the valve side of the rocker arm in comparison to the pushrod side. A 1.5:1 rocker arm will move a valve 1.5 times the lift of the cam, assuming all things are in proper working order. If your cam has a lift of . 4 inches, multiply by 1.5 to get .
Can I use roller lifters on a flat tappet cam?
It is possible to run hydraulic flat-tappet lifters on a solid flat-tappet cam, and hydraulic roller lifters on a mechanical roller cam. Running hydraulic lifters on a solid grind raises the rpm points at which peak power and torque occur compared to using solid lifters on the same solid cam.
What is the rocker ratio for a roller rocker?
In addition to offering roller bearings, most roller rocker setups are designed with a more aggressive rocker ratio. For example, they’ll sometimes go from 1:1.4 to 1:1.5. It is this change of ratio that can provide power increases—don’t worry, more on this soon.
What would happen if you put roller rockers on a stock engine?
In the case of a completely stock engine, the high-ratio roller rockers probably would have only lost power. With most classic cars, recipes for power usually go in this order: Start with the cylinder head. Then, go to more compression and more cam. After that, reinforce the bottom end so it can be revved higher.
How much do roller rocker arms increase lift?
For our first set of tests with the stock head, we compared stock rocker arms with a 1:1.26 ratio to the 1:1.5 ratio roller rockers. The ratios increased the 0.295 inch of lift to 0.372 inch and 0.446 inch, respectively. The high-ratio rocker arms did well at the peaks, picking up about 5 percent more torque and power.
Do rocker arm ratios affect engine performance?
The results were predictable—in each case, the engine made more power at high rpm and lost some power in the lower ranges. For our first set of tests with the stock head, we compared stock rocker arms with a 1:1.26 ratio to the 1:1.5 ratio roller rockers. The ratios increased the 0.295 inch of lift to 0.372 inch and 0.446 inch, respectively.
