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THR Thunder Stock rules changes announced


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THR Thunder Stock rules changes -- Released June 17, 2007

 

Effective immediately, THR Management Team announced today to amend the following two (2) rules for the former SAS Road Runner Class which is listed below relating to Suspension and Carburetors. These amendments for the former SAS Road Runners is in an attempt to help promote closer competition between them and the former THR Hobby Stock Class which now makes up the all new THR Thunder Stock Class.

 

Please add the following amendments to your current 07 rule book. Reminder, you must claim which rules you are declaring, Hobby Stock or Road Runner and there is no mixing of the two set of rules. A special thank you to the former THR Hobby Stocks for your support.

 

Jack Sandefur

Thunderhill Director of Tech/Pit Operations

 

SUSPENSION

 

a) FRONT

 

1.) Each UPPER CONTROL ARM must be a factory stock control arm and in

the factory installed position and on the stock mounts, except that spacers may be used to adjust the wheel camber and castor. Modification or bracing/reinforcing of either upper control arm is NOT allowed. All ball joints must be stock type and mount in the stock location.

 

2) Each LOWER CONTROL ARM must be a factory stock control arm and

mounted in the factory stock position on the front clip/frame. Modification or bracing/reinforcing the lower control arm is NOT allowed.

 

3) If factory stock or OEM springs are used, they must be the factory height. A height difference between the two springs of 1/2 inch will be allowed.

 

4) A left to right height tolerance of 1/2 inch will be allowed.

 

5) The front springs must be mounted in the factory stock mountings, without modification to the mount.

 

6) Any rated racing spring is allowed but they must be identical height between the left and right. No tolerance is allowed.

 

7) Front weight jacks are NOT allowed in this class.

 

8) None Adjustable spring spacers on top of the spring or on the bottom of the spring are allowed. Spacers must be the same left to right.

 

9) Spring rubbers may be used. All other existing suspension rules still apply.

 

10) Metal control arm bushings are allowed.

 

11) The camber and caster may be changed.

 

12) The stabilizer bar must have all of the factory stock link parts. All of the parts must be installed in and maintain an original factory configuration, including the same height right to left side and all bolts tight.

 

13) Adjustable spring spacers are NOT allowed.

 

b.) REAR

 

1) The rear suspension may be either leaf or coil springs, whichever is

factory stock for the year and model of the car.

 

2) The rear springs must be mounted in the factory stock locations and

using factory stock mounting parts.

 

3) Rear weight jacks are NOT allowed.

 

4) The rear springs must be equivalent to the factory stock spring and

both springs must be the same height. A 1/2 inch tolerance is allowed.

 

5) Rear racing springs must be identical height left to right.

 

6) Non adjustable spring spacers are allowed on the bottom or top of

the spring.

 

7) Adjustable spring spacers are NOT allowed. If rear sway bar is used, the stabilizer bar must have all of the factory stock link parts. All parts must be installed and maintained in original factory configuration.

 

d) CARBURETOR

 

1) A box stock HOLLEY MODEL 4412-500 CFM or the box stock 350 CFM

Model 7448 carburetor is allowed. The Model 4412 HP series is NOT an

option. If in doubt, check with the Tech Inspector.

 

2) The following changes to the carburetors are permitted. These apply

to both the 4412 and the 7448. Circle track float system is allowed.

 

a) The choke butterfly and shaft may be removed.

 

B) The power valve and the jets may be changed. Power valve must be

functional.

 

c) The butterflies may be drilled with one hole no larger than 3/16

inch diameter.

 

d) The throttle shaft must remain stock with no thinning or cutting in

any matter.

 

e) The main body and metering block may not be reworked in any way.

They must remain box stock.

 

f) The amount of holes and their location must remain as manufactured.

Additional holes and passages will NOT be permitted.

 

g) Additional screw-in pressed in bleed holes in the main body or

metering block will NOT be permitted.

 

3) A carburetor spacer of not more than 1.250 inch, including gaskets,

is allowed as spacing between the carburetor base and the manifold

surface. The holes in the spacer must be the same dimensions from top

to bottom of opening (no tapered hole spacers.)

 

4) The air cleaner must have a metal top and bottom with a paper filter

element.

 

5) Tubes, Funnel, ram air devices or any other device to help control

air flow is NOT allowed.

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