2008 Sportsman Rules

Body, Chassis and Frame rules see Modified Rules Except for below:

No cars will be allowed to add ballast weight outside of the vertical planes of the frame rails and must be stationary while racing and be securely fastened.  Minimum weight 2500 lbs (SEE ABOVE).

(Same as Modifieds)

Left Rear McCreary American Racer 33

Right Rear McCreary American Racer 38

Left Front McCreary American Racer 33

Right Front McCreary American Racer 33

Buffing, cutting, grooving, or sipeing will be allowed.  No tires softened.  Tires will be checked with durometer on scales after feature events.

Locked in tire prices for the season will be posted at the track.

This class is reserved for North American passenger car V-8 engines with cast iron blocks cylinder heads.  A maximum of 358 cu. in. plus a 4 cu. in. wear allowance.

ONLY NON-PORTED STOCK OEM CAST IRON BLOCK AND HEADS ARE ALLOWED.  ALL ENGINE PARTS MUST HAVE CASTING OR PART NUMBERS ON THEM FOR IDENTIFICATION.

All engines must maintain stock bore and stroke combinations.

Engine                                                              Maximum Overbore

Chevy 350 C.I., 4.00” bore x 3.480” stroke.                    +.070”

Chry 360 C.I., 4.00” bore x 3.578” stroke.                      +.010”

Chry 340 C.I., 4.04” bore x 3.313” stroke.                      +.060”

Ford 351 C.I., 4.00” bore x 3.5” stroke.                          +.060”

ENGINES MUST REMAIN STOCK AS MANUFACTURED WITH THE FOLLOWING EXCEPTIONS:

1.   BLOCKS:  The engine block and all internal parts must meet stock specifications for its make. Bow Tie, Dart other performance type blocks allowed.

2.   CYLINDER HEADS:  Only cast iron OEM stock production heads that pass the ball check and were produced by Chevy, Chrysler or Ford with part and casting numbers approved by DIRT are eligible to run.  Chevy bow tie, Chrysler W-2 and Ford performance heads are all allowed providing they meet the rules and not fall into the category of unfair competition.  Dart heads are allowed up to 200 CC.  The Chevy Vortec and the Ford GT 40 are not allowed.  Cylinder heads must be from the same manufacturer as the engine block.  Sand blasting, bead blasting, acid dipping, porting, polishing and welding are prohibited.  Milling or angle milling of the cylinder head to any amount is allowed.  No epoxy or coating of heads is allowed.  No relieving or unshrouding of valves in the combustion chamber.  Valve head sizes are optional providing they maintain stock OEM positioning in valve guides (distance apart angles).  Valve guide liners are allowed.  Valve material must e one-piece solid steel or stainless steel, no titanium or sodium filled valves allowed.  The only titanium allowed in these engines is the valve spring retainers.  Any carbon fiber engine parts are illegal.  Any amount of valve seats per cylinder head may be installed for the purpose of repairing a head.  Any angle valve job will be permitted as long as it is done on a machine that cuts concentric to the valve guide center.  Valve stem maximum and minimum diameter, plus or minus .005” must be as follows:  Chevy 11/32”, Ford 11/32”, Chrysler 11/32”.  No hand grinding, sanding, blending or de-burring where a cutter or stone leaves off.

THIS IS A NON-PORTED CLASS.  Inspection will be conducted with the head on the engine but the method of checking may require the removal of the intake and exhaust manifolds. Heads will be removed only to surrender to the Thunder Mountain Speedway officials for appeal. The method checking the legality of heads will include a visual inspection for grinding and polishing and the use of the following gauges that are available from DIRT Headquarters:

1)   A go/no-go gauge will be used to determine the height of the intake port.  Gauges are available for Ford, Chevy and Chrysler.

2)   A go/no-go gauge will be used to determine the height and width of the exhaust port.  Gauges are available for Ford, Chevy, and Chrysler. 

3)   A go/no-go intake runner ball will be used to determine the dimension of the intake runner.  Gauges are available for Ford, Chevy and Chrysler.

4)   An exhaust valve seat ball consisting of a .531” diameter ball bearing welded to a ¼” flexible shaft will be used.  With the valve fully opened, the ball will be placed against the valve stem.  If the ball drops down through the valve seat in any position around the full circle of the valve stem, it will be deemed illegal.

5)   An intake valve seat ball using the same procedure as described for the exhaust side will also be used, except the ball size will be .787”

NOTE:  This method of checking the head will hold true with a hot or cold engine.  No extra time will be given for the engine to cool off. 

Special note:  Anyone found to be illegal in any way in the cylinder head area will result in complete disqualification, losing all moneys and points for the night.

Any Steel or cast iron crankshaft is allowed providing it maintains stock stroke as manufactured for the engine block used.  Crankshaft must weigh minimum of 48lbs. 

OEM stock production or aftermarket solid steel rods are allowed.  No titanium or aluminum.  Maximum rod length is 6”.  No polished rods are allowed.

Any brand, 3 ring flat top aluminum pistons only.  No coating of any kind is allowed.

Any steel or cast iron, stock OEM vibration dampener is permitted providing it is not machined or altered in any way.  No fluid or friction dampeners are allowed.

Any make hydraulic or flat tappet allowed.  No roller cams, roller gear driven cams, mushroom lifters or lash caps are allowed.  Shaft rockers not allowed.  Stud girdles are allowed.  Engines with stock OEM shaft rockers are legal.  Roller rockers with optional ratios are legal.  Lifters must maintain stock OEM diameters.  Lifter bores must remain in stock OEM positions and angles, but may be re-bushed for wear.  A flat steel lifter galley plate may be used to prevent engine damage in case of push rod failure.

Must be a stock passenger car, cast iron 2-barrel intake manifold only.  No porting, polishing, welding, matching or acid dipping is allowed.  An optional aluminum four barrel as cast box stock, spec manifold may be used.  No work of any kind may be done on this optional manifold. 

The manufacturer is Brodix part #HV1011 for Chevy, Edelbrock part number 2915 for Chrysler 340 heads, Edelbrock part number 2920 for the Chrysler W-2 head, and Edelbrock part number 2981 for the Ford 351 Windsor.

Any American stock OEM 2 barrel carburetor up to 1-11/16” throttle bore with no adapter plate is legal on cast iron manifolds.  The Holley carburetor, part #4412 is acceptable and must run a maximum spacer adapter of 1 1/16” including gaskets.  No modifications of any kind will be allowed to these carburetors except those listed below (box stock only).  Conventional round type air cleaners only.  Air cleaners that provide ventilations through the top cover (such as the K & N brand) are permitted.  No air induction plastic carburetor inserts or other devices to direct air into intake.  No air diffuses are allowed.

CARBURETOR MODIFICATIONS ALLOWED ARE LISTED BELOW, ANY OTHER MODIFICATION NOT MENTIONED IS NOT LEGAL.

            -Holes drilled in the throttle plates for proper idling.

            -Drilling, tapping and plugging of unused vacuum ports.

            -Welding of throttle shaft to linkage arm.

            -Drilling of idle or high-speed air correction jets.

-Milling of center carburetor body metering block surface a maximum of .015” on each side.

-Removal of choke plate and shaft.

-The jets may be changed as needed.

Stock OEM distributors and coils only.  No trigger ignition systems allowed.  No Mallory or Accel ignitions may be used.  On H.E.I ignition systems, coils must remain in the distributor if stock OEM, all H.E.I. distributors must remain as manufactured.  On point type distributors, coils must be stock.  With any system used, only one coil will be allowed on the car.

No dry sump system is allowed.  Oil must be in steel pan only.  Oil pan must have ¾” inspection hole for connecting rod verification on left side of pan.  No external oil pumps or Accusumps are allowed.  Oil coolers will be permitted providing they are mounted under the left wing or under the hood only.

Must be cast iron only.  Radiator fan must be steel only.  No electric cooling fans or pumps.

Must remain in and be driven as stock OEM equipment.  No electric fuel pumps are allowed.

PLEASE NOTE: Any post race tear-down on cars in this class must have finished in the top five, including the car of the protester. Protesting car MUST also submit to the same tech inspection as that of the car being protested. This type of procedure will prevent any unnecessary “grudge” tear-downs of cars. A $200 tear down fee must be presented to head tech inspector by protesting driver along with written protest no more than 10 minutes after completion of feature.