Texas Pro Racing Association

2009 TxPRA Pro-Stock Rules

Class designated at: *9.0 lbs per cubic inch.

Cars using "stock" blocks have a minimum weight of 1300 lbs. and all others have 1350 lbs. minimum weight. See Weights. Click HERE for a table of minimum Pro-Stock weights based on engine size.

Body Any VW Type I, III, Ghia, or NEW BEETLE may be used. No convertibles accepted. Metal Bodies only. Must be full fendered, with front and rear hoods. Running boards not required.
All glass can be replaced with 1/8" Polycarbonate material, such as Lexan MR 4000.

Stock drip rails may be removed. Maximum 4" top chop. Minimum roof height 46". Body may be channeled over frame. Body may not be lightened by drilling holes. Body may not be sectioned. Minimum height of door measured from bottom to window crease is 24". See General Rules. Must retain original windshield and rear window angles. Body may not be otherwise altered in height, length, width, or contour. Windows may be flush mounted to the body openings. Windows need not be operative, but must be closed during competition.

Class designation on rear quarter window in 3" letters and permanent number in 6" numbers.

Fiberglass or carbon fiber may be used for fenders, hood, deck lid, aprons, and doors as long as stock appearance is retained, however rear fenders may be widened to accept larger tires. Maximum dimension to outside of rear fenders is 68". Minimum is 58". Rear fenders may be raised on body for tire clearance but must be mounted at least 2" below quarter window measured 25" back from the door opening. One piece fiberglass front ends are acceptable. Fenders must be securely mounted to body. Inner edges may be cut for clearance. Deck lid may be fabricated to clear carburetors or injectors. Front fenders may be raised for tire clearance, but must not be mounted above the front hood, measured at the center line of the front tire opening. Maximum dimension to the outside of the front fenders is 66" measured to the outside of the fenders. Minimum is 58". No floating mount front hoods. The leading edge of the front end may be squared off and an aero lip added for stability. Maximum measurement from front of door to nose 5" more than stock. See PRA General rules. Drooped front ends prohibited.

Ground clearance must remain at 3". Both doors must be fully operative and can be opened both from the inside and outside. Super Beetle bodies may be mounted with a standard Type I front end.

All cars must be a finished product and can compete at only one race in primer. Cars must be complete during qualifying and eliminations, i.e. deck lids, aprons, etc.

Wings Wings are not allowed in Pro Stock. A spoiler of single plane design is permitted. It must be mounted below the lowest point of the rear window and not more than 42" wide, except on New Beetle bodies, whereas the maximum width is restricted to 2" outside of the stock rear hatch opening on each side. Maximum height 4" from mounting point. Maximum gap between body and spoiler 1 inch.

Engine One 4 cylinder opposed pushrod, 2 valves per cylinder, of VW configuration. One spark plug per cylinder. Carburetors, mechanical fuel injection or electronic fuel injection . No turbos, superchargers, nitro, or nitrous oxide permitted. Engine must be in stock location. The term "stock block" is in reference to the factory cylinder head stud pattern.

Fuel Gasoline only. No nitrous oxide or nitro methane allowed. No oxygen bearing additives allowed.

Fuel System Aftermarket fuel tanks or cells are acceptable. Must be located outside the driver's compartment. A bulkhead of at least .032" minimum thickness metal must be between the fuel tank and the driver's compartment. Magnesium not permitted. No device which reduces the temperature of the fuel can be mounted on the car.

Transmission

Any conventionally mounted VW or Porsche transaxle permitted. Mendeola brand, VW-style, gearboxes are permitted. Must have a neutral. Reverse required. Reverse lockout device mandatory. Locked rear ends allowed. Welded spider gears not allowed.

Electronic Devices No electrical, or air operated, devices such as delay boxes, throttle stops, or timers may be used. No device that functions to operate the vehicle may be used. DATA GATHERING DEVICES are limited to one playback tachometer. Computers are not permitted during qualifying or eliminations.

Frame Any type frame permitted providing it meets the safety requirements. Must have automotive type front and rear suspension commonly used by an automobile manufacturer. Must have one hydraulic shock absorber for each sprung wheel. Air adjustable shocks not allowed. Frame must be certified by NHRA if running 9.99 (6.39 1/8 mi.) or quicker.

Steering Minimum steering wheel diameter is 13". Butterfly wheels not permitted.

Wheels and Tires Must use automotive-type wheels. Racing slicks permitted. Wire or motorcycle wheels not permitted. Minimum wheel size 13".

Ground Clearance Ground clearance of 3" minimum from front of car to 12" behind center line of the front axle is required. 2" minimum for remainder of car except for oil sump and exhaust headers.

Roll Bar Roll cage required with side bar. See PRA General Rules & current NHRA Rulebook.

Wheelbase Maximum wheelbase is 97". Minimum wheelbase is 92". Axles and body location must remain as originally produced. Maximum wheelbase variation left to right is 1" but cannot exceed the 97" wheelbase.

Interior Minimum one front seat. It may be a properly braced and reinforced fiberglass or aluminum bucket. No center steering. Dash board must be retained but may be modified. Doors must have panels. Headliner not required. Floor and firewall required constructed of steel or aluminum.

Electrical Battery must be securely mounted outside of driver's compartment. All cars must be self starting. Master cut-off switch is required. All cars must have one working tail light.

Brakes Must be hydraulically operated. Minimum two wheel rear brakes operated by a foot pedal mounted in a conventional location. (Front brakes recommended.)

Helmet Helmet must meet or exceed Snell 2000 or SFI 31.1A, 31.2A, specifications.

Protective Clothing Jacket and pants meeting SFI Spec. 3-2A/5 required. Drivers must wear approved gloves and shoes or boots meeting SFI 3.3/5 mandatory.

Seat Belt, Shoulder Harness Driver restraint system meeting SFI Spec. 16-1 required. Restraint system must be updated at 2-year intervals from date of manufacture. Crotch strap is mandatory.

Window Net Ribbon type window net is required.

Neck Collars Must be worn by driver. Must meet SFI 3.3

Weight Minimum weight including driver is 1300 lbs. for cars using engines with factory stock Type I cylinder head stud pattern. A maximum 4 studs per cylinder allowed. The minimum diameter for a head stud is .281". Minimum weight for all other engine configurations is 1350 lbs. Click HERE for a table of minimum Pro-Stock weights based on engine size.

Engine Verification

At each TXPRA points event the event winner will be required to have their engine checked for accurate displacement/cc claimed during the event.

The process for accurate verification will be that the TXPRA Tech Director (Clarke Watts Jr.) will assist the competitor in removing one cylinder head from the engine. At this time TXPRA Tech Director will accurately measure the "bore & stroke" and verify 9lbs per cubic inch was followed during the event.

Should the competitors engine not match the "claimed" displacement/cc (over or under) the TXPRA Tech Director will disqualify the competitors win. Points & winnings will not be awarded to the competitor during this event.

The same process will take place should a TXPRA record be set as well. At the conclusion of the event should the competitor wish to claim the "record" he will notify the TXPRA Tech Director to assist in cylinder head removal.
No verification No Record!

Safety All cars must meet NHRA safety standards.