Classic Inlines
603 W Pecos Ave
Mesa, AZ 85210


 
Rocker Arm Options

Stock Non-Adjustable Rocker Assembly - Rebuilt 1.5 ratio, stock non-adjustable rocker arm assembly, fully assembled and ready to bolt on. Recommended for stock applications where the cylinder head and/or block have not been milled more than a total of .125".

Stock Adjustable Rocker Assembly - Rebuilt 1.5 ratio, stock adjustable rocker arm assembly, fully assembled and ready to bolt on. Requires adjustable ball and cup style push rods (sold separately) if you are replacing stock non-adjustable rocker assembly. Recommended for stock applications, mild performance motors, or when the cylinder head and/or block have been milled more than .125" to increase or maintain the C/R.

Stock High Ratio Rocker Assembly - New 1.6 ratio, adjustable rocker arm assembly, fully assembled and ready to bolt on. Requires adjustable style ball and cup push rods (sold separately) if you are replacing a stock non-adjustable rocker assembly. High ratio rocker arms increase valve lift, increasing air flow and performance, especially at low and mid range RPM's. Dyno testing only showed a peak gain of 2 HP, however it also showed an average gain of 10 HP, as compared to a stock 1.5 ratio rocker assembly on a modified log cylinder head (see comments below). Recommended for stock applications, mild performance motors, or when the cylinder head and/or block have been milled more than .125" to increase or maintain the C/R. When using single valve springs, extreme caution must be observed to prevent coil bind (dual springs are highly recommended).

Roller Tipped High Ratio Rocker Assembly - New 1.6 ratio, adjustable rocker arm assembly, fully assembled and ready to bolt on. Requires adjustable ball and cup style push rods (sold separately) if you are replacing a stock non-adjustable rocker assembly. High ratio rocker arms increase valve lift, increasing air flow and performance, especially at low and mid range RPM's (see comments below). When using single valve springs, extreme caution must be observed to prevent coil bind (dual springs are highly recommended).

Full Roller Rocker Arm Kit - 1.65 Rocker Ratio - Kit includes oil through ball and ball push rods and lifters. The stock oiling system (through the shaft) is eliminated when you remove the stock rocker assembly to install this kit. As such the lifters and pushrods must be replaced with an oil through type, such as those used in SBF applications. High ratio rocker arms increase valve lift, which in turn increases air flow and performance, especially at low and mid range RPM's (see comments below). When using single valve springs, extreme caution must be observed to prevent coil bind (dual springs are highly recommended).



Benefits of Adding High Ratio Rocker Arms

One proven way to increase power is by decreasing the valve-train friction. Two of the biggest friction "hot-spots" in any valve-train, are those where the rocker fulcrum rides on the shaft (or studs), and where the tip of the rocker comes in contact with the valve stem. In basic, simplified terms, the more energy your engine exerts to overcome these high-friction contact points, the less torque it exerts to the rear wheels. If you eliminate the metal to metal contact (rubbing), the engine will spend less energy doing the same work.

By placing a roller on the tip of the rocker where it comes in contact with the valve stem, the rocker is able to roll across the valve as it travels through its cycle, instead of sliding back and forth across the valve stem. Beside the obvious friction created here by non-roller tipper rockers, serious side loads are placed on the valve stem. Basically the tip of the rocker arm is dragged across the top of the valve, while the valve travels up and down in the valve guide, which results in excessive guide wear and loss of power.


While most will assume that the only benefit of roller rockers is reduction in friction, the other benefits of aftermarket rockers include true, blueprinted, at-the-valve ratios and precision motion. Another time-honored way to increase power with rocker arms is to change the ratio of the rocker. The benefit of increased rocker arm ratio is the valve is opened a little further and faster, allowing more air in and out of the engine, thus creating more power. Changing from a rocker ratio of 1.5 to 1.6 generally adds about 3 degrees of valve duration. The net result is you are effectively changing your cam specs without changing your cam.

In a recent dyno session we added a high ratio rocker assembly to an otherwise stock 250ci engine (accept for improved induction) to verify any improvements. At first we were disappointed, as maximum power was only increased by 2HP. However, after looking at the numbers we noticed the average HP was increased by 10HP. Therefore if peak only went up 2, and the average was 10, then the lower and mid range numbers had to be better than 10HP. Thus making the swap a viable means of increasing power and performance.

The Roller Tipped Rockers come fully assembled a on a new shaft, ready to go. Just remove your old rocker assembly, bolt on the new roller tipped assembly, and adjust the lash. It's that simple. The Full Roller Rockers require assembly on the head, but it is a relatively simple procedure. Remove the old assembly, bolt on the spacer bars, install the rockers in pairs, and adjust (see pictures below).  

A)  Installation of  Roller Tipped Rockers or Full Roller Rockers requires pushrods designed to facilitate adjustable rocker arms. Your stock rockers may or may not be adjustable in design, thus the pushrods may be incorrect.   Prior to installation, verify your existing pushrod type.  

B)  Installation of Full Roller Rockers will require  the elimination of the stock rocker arm shaft, thus eliminating the stock oiling system as well. To retain oiling to the valve train, the pushrods and lifters must be changed to an oil through design.

stock head with
rockers removed
head with spacer
bars installed
with full roller
rockers install
view of spacers
and rockers
stock verses full
roller rockers
stock verses full
roller rocker
customer install
customer install
customer install




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