
Not all Rockers are created equal. GM Spec is 1.5:1 and after measuring hundreds, we found that some are just 1.2:1. In fact - you'll find an average of 3 1.2's on the intake valves of almost any engine. Installing New Rated Rockers gets you an average of 5-6hp and Torque off the corner and at the top end and more importantly faster acceleration. If your rockers are good - you'll get the same performance increase.
A rocker arm in your 602 engine takes a rotating cam lobe and turns it into an up and down motion that opens and closes the valves.
Here's how it works. As the cam comes around, the cam lobe pushes the lifter and pushrod up, which lifts the back side of the rocker arm. When the backside lifts, the other end of the rocker rotates to push down on the valve stem; compressing the spring. As the cam lobe rotates away, the rocker arm rotates back and the spring pressure closes the valve.
Rocker Arm Ratio determines how much power it can transfer to the valve stem. In a GM Crate, the GM Spec rocker arm ratio should be 1.5 to 1. Meaning that the rocker should move the valve 1.5 times the height of the cam lobe which is 0.435 for intake and 0.460 for exhaust. Since the intake is smaller to start with, the lift is critical.
If you have a crummy rocker arm - your Valve will open significantly less than it should. Less "Valve opening" on an intake valve means less power. Therefore you want your best rockers on your intake valves.
Here's how our KillerCrate ROCKER RATING Service works:
1. Purchase the ROCKER RATING service from the KillerCrate Store
2. Please send your set of rockers with the Order Number # and a note with your return Address in the box to:
3. Ship your rockers to KillerCrate. We recommend a USPS Small Priority Box which is about $8 USD
4. We use a Special Rocker Rating Machine we created to measure all your rockers. Rockers are rated as Green, Yellow or Red.
Green are the best and go on Intake Valves. Yellow are rated for Exhaust Valves and Red are really not good enough to use. Sometimes we have rockers in stock to replace any Red Rated Rockers at an additional cost if necessary.
5. KillerCrate Ships your Rockers Back in Marked Bags to indicate where they should be installed.
The Service May take up tp 2 weeks with shipping. Therefore, we recommend that you plan ahead. Many of our clients who have multiple motors take the rockers from one motor and send them in. Then when they change the springs, they change the rockers too. Then send in the second set of rockers.
Crate racing was intended to level the playing field. However, after several Track Championships and winning 7 out of 14 Races at Devils Bowl in 2016, we can tell you that Not all 602 circle track Crate Engines for Pro Stock, Thundertrucks, Sportsman Modifieds and other types of crate racing are created equal. If you want to run up front - there are a few secrets that you need to know.
With the proper break-in technique and a little magic - your motor WILL create MORE LEGAL horsepower and last longer. The correct distributor phasing, timing marks, race-prepped carburetor, carb spacer and better Valve Springs, Rated Rockers can all significantly improve performance.
At KillerCrate, we make it easy to buy a quality Race-Prepped Crate engine, deliver it to your doorstep and provide outstanding service. We'll even provide some setup tips. That's because we want you to join the long list of KillerCrate Race Teams who reach victory lane.
Contact us today and let us help you with your next crate engine.
Why Buy from KillerCrate?
• Shipping to your doorstep! You don’t have to drive several hours to pick up your motor.
• Race Packages for your Track. We offer configurations specifically for local track rules.
• Fast turnaround time. Did your old motor blow this weekend? During race season, call us on Monday morning and we can usually have you back on the track by your next race!
• Guaranteed Performance specs on Race-Ready motors. You don’t need to wonder if you’ve got a “good one”; because if it’s not great, it doesn’t go out the door.
• Winners Bonus*. If you win a feature in your first month, you’ll get up to a $50 KillerCrate Gift Certificate!
• We’re racers too. We run what we sell. We are always testing to make our product better and then sharing what we learn with our customers!
Bob Godgart and Bobby Hackel
KillerCrate
Bob Godgart and Bobby Hackel Run KillerCrate. We're racers who have won track championships at many levels of dirt and asphalt racing.
We pride ourselves on our outstanding customer service and have helped many crate racers reach the winners circle for the first time. If you have questions, Message us on Facebook.