Thunder Car Rules and Specifications

There will be in an inversion each week, unless special event!

Body:
A. Must be American OEM stock appearing (ex. Regal, Monte Carlo, Camaro, Chevelle, or Firebird).
B. Stock steel bodies. Aftermarket stock type steel and aluminum bodies are ok.
C. Late Model straight sided bodies allowed but must add 200lbs.
D. Nose panel and bumper cover must match body being used (Ford/Ford, Chevy/Chevy, Mopar/Mopar).
E. Must use stock OEM roof panel or aftermarket stock type roof panel.
F. All holes in body and floor pan must be covered.
G. Maximum Rear Spoiler Height of 6 inches.
H. Spoiler cannot be wider than body.
I. ALL bodies must meet track tech approval.
J. Body hulling and inclosed cockpits ok.
K. Front and Rear bumper must be no wider than body, no sharp edges. 

Tires:
A. Hoosier D-55 Spec tire ONLY!

Engines:
A. Engine must match body being used (Chevy/Chevy, Ford/Ford, Mopar/Mopar).
B. 362 cubic inch maximum in Ford/Chevy. 374 cubic inch maximum in Mopar.
C. Block must be OEM with .060 Maximum overbore.
D. Flat top pistons in Chevy and Ford and cannot be above deck of block.
E. Crank must be OEM steel or cast with MFG numbers in place.
F. No lightening of crank except for balancing purposes.
G. Rods- any steel (I beam). Must match block and crank being used.
H. Chevy   350: Stroke- 3.480     Rod length- 5.700   
     Ford     351: Stroke- 3.500     Rod length- 5.995
    Mopar  360: Stroke- 3.580      Rod length- 6.123
I.NO dry sumps allowed.

Heads:
A. Must be steel OEM Chevy Bowtie, Dart, or World Product. Ford Sportsman, World Product, or Dart cast iron heads allowed a maximum valve
size of 2.05 intake/ 1.60 exhaust.
B. No titanium valves. Stainless steel permitted.
C. No titanium retainers allowed.
D. No porting or polishing allowed.
E. Roller rocker arms are permitted.
F. Flat tappet cams only.
G. Guide plates and screw in studs ok.

H. May run GM Performance 602 Crate Engine.

Intake:
A. Aluminum intakes permitted. 

Carburetors:
A. 750 CFM maximum. 

Fuel and Fuel Cell:
A. Racing gas only.
B. Fuel Cell Mandatory with steel outer shell.
C. No electric fuel pumps. 

Ignition Systems:
A. Stock or aftermarket ignition permitted.
B. No magnetos. 

Brakes:
A. Any 4 wheel drum or disc system allowed.
B. Aftermarket dual master cylinders permitted.
C. Proportioning valve ok. 

Wheelbase:
A. 108 inches minimum.
B. Engine must be located so that the number 1 spark plug in no further to the rear than the ball joint.
C. Front of engine must be in front of crossmember. 

Rear End:
A. No quick change rear ends allowed.
B. Stock OEM rear ends ok.
C. Ford 9 inch rear ends allowed.
D. Ford type floater rear ends allowed (NO bird cages). 

Weights & Suspension:
A. Stock rear suspension cars may weigh 3000 pounds, all other cars with modifications to rear suspension 3100 pounds.  Cars with GM 602 Crate Engine weigh 2900 pounds.
B. No coil overs or coil over eliminators allowed. No lift bars. Rear coil springs must be mounted on top of axle housing minimum of 25 percent of spring must be on axle tube.
C. Rubber biscuit or spring pull bar allowed. Spring type minimum of 5 inch diameter spring. One shock on top of rear end allowed.
D. All springs must be a minimum 5 inch diameter, one per wheel. One shock per wheel.
E. No bird cages allowed. All suspension mounts must be welded to rear axle housing and frame. No four bar suspension.
F. Three bar or leaf spring ok. Panhard bar allowed, J-bar ok may be attached on either side of frame but must be attached to rear axle on opposite side of pinion (no short bars).
G. Heim joints allowed on trailing arms may use steel or aluminum tubes. 

Flywheel:
A. Steel or aluminum flywheels ok. 

Clutch and Transmissions:
A. Stock OEM type transmissions allowed.
B. Bert, Brinn transmissions allowed.
C. Multi disk clutches allowed. 

Front Suspension:
A. Frame or front clip must be factory OEM.
B. Front frame section must be full clip extending to the firewall.
C. Rear sections may be fabricated from square tubing.
D. Frame may be connected by X-ing.
E. Tubular upper A arms OK.
F. OEM steering components allowed.
G. Rack and pinions OK.
H. Upper control arm mounts on frame may be aftermarket.
I. Lower control arms must be OEM for make and model of chassis. No altering of control arms or control arm mounts.  A-arms and spindles must be on original side of vehicle.  Any type spindle allowed.
J. Upper A-arm mounts and jack screws be center of spring pocket.
K. No aluminum steering parts except quickener and steering wheel.
L. Front crossmember cannot be altered except for fuel pump clearance and motor mounts. 

Wheels:
A. 12 in maximum Steel wheels only.
B. Wide 5 steel wheels with aluminum adapters and spacers OK.

C. Steel Beadlocks OK ON REAR ONLY.

Protest:
A. Pull one head check bore, stroke, lifter, carb., and head - $300.00.
B. Pull oil pan, head, and one rod (inspect) - $375.00.
C. Track tech receives $50.00 of protest fee for inspecting engine.
D. Track official may inspect any car or driver’s condition at any time.
E. Official may give tolerances on some rules.
F. Track officials decision is final. 

Safety:
A. Firesuits required; gloves and shoes recommended.
B. Roll bar padding around driver’s head area required.
C. 5 point safety belts required.
D. High back aluminum seat and padding required.
E. Window net or arm restraints required.
F. Helmet and face protection required.
G. Working fire extinguisher required.
H. Kill switch must be clearly marked and in easy reach of driver.
I. All holes in firewall and floor pan in drivers area must be sealed.
J. Drivers head must be below top of roll bar.
K. Must have minimum of three windshield bars in front of driver’s cockpit. 

TOW LOOP IS REQUIRED FOR WRECKER PURPOSES.