2026 FORMULA FORD CHALLENGE SERIES

Rules & Regulations

 

 

I. Formula Ford is comprised of 3 distinct Formula Ford classes for single seat, open wheel racecars.

1. HF Historic Ford: First generation 1967-1972. A specific list of eligible chassis.

2. CF Club Ford: Second-generation post 1972 with outboard suspension on at least one end as originally manufactured. A specific list of eligible chassis.

3. PCF Post-Club Ford: The third generation raced through the 1987 season using front and rear inboard suspension and vertical dampers not activated by bell cranks.  A specific list of eligible chassis. Other post 1981 cars may be accepted at the sole discretion of the FFCS Executive Committee.

​

II. Engine - Detailed engine rules are listed in Appendix I National Vintage Formula Ford Association (NVFFA) Engine Rules & Regulations

Engine: 1600cc OHV crossflow Ford pushrod engine

Formula Ford is a restricted class using the standard Ford Motor Company 1600 cross flow pushrod engine.   The engine must remain as delivered from FoMoCo with the exception of the allowable modifications, changes, or additions as stated herein. There are no exceptions. IF IN DOUBT, DON’T.

 

As additional OEM parts (particularly engine parts) become obsolete there will be a need to update these rules to allow suitable replacement parts. However, no new part, change, or modification is permitted, beyond those allowed in these rules, until it has been reviewed, approved, and published into these rules. 

 

III. GENERAL RULES APPLICABLE TO ALL THREE CLASSES

1.0 Definition

a.  A formula for single seat open wheel racing cars using standard Ford 1600 "crossflow" pushrod engines, with           firewall, floor, and safety equipment conforming to these rules

b.  Formula Ford is a restricted class.  Therefore, any allowable modifications, changes or additions are as stated           herein.There are no exceptions.  IF IN DOUBT, DON'T. Homologation is required for all cars registered after             January 1, 1983

​

2.0 Tires: 

a. The following are the only allowable spec tires for all classes (Wet or Dry):

Front: Avon ACB9 5.0/22.0-13 A29 Compound14297

Rear: Avon ACB9 6.5/23.0-13 A29 Compound14298

                                                 or

Front: Hoosier VFF 44165, 135/545-13

Rear: Hoosier  VFF 44170, 165/580-13

 

b.  Single event exemption for first-time entrants with non-compliant tires at the sole discretion of the FFCS

     Executive Committee (entrant ineligible for Series points or awards).

 

c.  No mixing of makes is allowed. Additional grooving or hand-cutting is not allowed.

​

3.0 Wheels
Wheels are unrestricted except that:
a. Material is unrestricted providing it is metal. (Historic Fords must be pressed steel disc type)
b. Diameter shall be thirteen (13) inches.
c. Rim width shall not exceed 5.5 inches.
d. Wheel covers, wheel fans, or any device to fair in the wheel is prohibited.

 

4.0 Weight:

a.  1110 lb. All classes minimum weight as qualified or raced including driver and gear. 

b.  HF may choose alternative minimum weight of 925 lb. as raced, excluding driver and gear.  

 

5.0 Brakes
Unrestricted, except that calipers shall be cast iron, and rotors are restricted to ferrous material.

​

6.0 Clutch
The use of any single-plate clutch is permitted provided no modification is made to the flywheel other than changing points of attachment of the clutch to the flywheel, and provided that it has an operable clutch system.  Carbon fiber clutches are not permitted.

​

7.0 Transmission
Any transmission may be used with not more than four (4) forward gears and an operational reverse gear.
a.  The use of automatic and/or sequentially shifted gearbox is prohibited. 
b.  Electronic assisted gear change mechanisms and electronically controlled differentials are prohibited.
c.  Gearboxes with shafts that are transverse to the longitudinal axis of the chassis are not allowed. The sole

     exception are the gearbox final drive (crownwheel) shaft axis and final drive shafts (halfshafts). All change gears

     must be located in the case aft of the final drive.

​

8.0 Final Drive
Any final drive unit may be used except:
a.  Drive shall be to rear wheels only.
b.  The differential cannot be modified in any way to limit its normal function. Torque biasing, limited slip, and locked

     differentials are prohibited.

​

9.0 Fuel Tanks
a.  All fuel tanks must be properly secured. The original elastic cords are in most cases inadequate. 
b . An FIA approved (or equivalent) road racing type fuel cell, properly mounted, with a non-vented filler cap, and           check valve in the venting system, is required for all cars. 
c.  This requirement includes a flexible bladder filled with foam surrounded by a metal enclosure. 
d  Tanks must be in the original location or, if relocated, be entirely within the chassis frame.
e.  Vent lines with check valve shall terminate outside of the car bodywork and be located at least 25cm

    (9.843 inches) to the rear of the cockpit.   

​

10.0 Fire System

a.  Cars must be equipped with a minimum of a 2-liter or 5.0-pound nontoxic, commercially available fire system.

b.  As a minimum there shall be two nozzles, one nozzle directed at the carburetor and one directed toward the

     driver.

c.  Actuation can be mechanical or electrical and must be within easy reach of the driver.

  

​​

11.0 Roll Bars: 

a.  The roll bar should be of sufficient height to protect the driver in the event of a roll-over, extending a minimum of

     2” above the driver’s helmet, with driver seated in normal position.

b.  The rear of the helmet shall not be more than 6” from the forward edge of the peak of the roll bar when

     measured in the vertical plane. 

c.  Roll bar design, materials, and fabrication must be consistent with sound engineering practice and of excellent

     workmanship, using at minimum 1.375" diameter x 0.187" wall mild steel tubing.

d.  Acceptable alternate sizes and material specifications can be found in the portion of the SCCA “General Competition Rules” (GCR) for 1979, Appendix Z, pertaining to roll bars (linked here).  This should not be confused

     with material specifications for roll cages, also included in Appendix Z.

e.  All parts of the roll bar that may come in contact with the driver’s helmet, must be padded with minimum ½” thick

     SFI 45.1 or FIA Type A high-density roll bar padding.

​

12.0 Head Rest

a.  Head restraint: There should be a substantial, padded head restraint within 3” (or less) of the back of the driver’s

     helmet. This restraint may be part of the seat, roll bar, or bodywork.

b.  Minimum area of 36 square inches and minimum 1” thick SFI 45.1 or FIA Type A high-density padding.

​

13.0 Presentation:

a.  All Formula Fords shall be presented with a clean and finished appearance in keeping with the spirit of vintage

     racing.

b.  Cars with a rough appearance or otherwise deemed inappropriately presented may be excluded by VRG/race

     officials.​

14.0 Modifications
a.  Any Historic, Club, or Post-Club Ford not in in original form, having modifications not in compliance with the rules

     of their class will be scored in the class where they are fully compliant.  
b.  Any Historic Ford running non-steel wheels will be scored as a Club Ford.  
c.  Cars with elements not in compliance with any class will be given a one-year waiver to achieve compliance.

     Failure to do so will result in ineligibility for points and awards at FFCS events.  
   
15.0 Additional Requirements
a.  Other safety related requirements shall be found in “VRG Rules, Section 3.0” available on-line at

     www.vrgonline.org.
b.  Where both FFCS and VRG rules apply, competitors are required to comply with all rules.  In instances where

     FFCS rules are more restrictive, the FFCS shall take precedence.
 

IV. HISTORIC FORMULA FORD REGULATIONS

1.0 . Definition

a.  Eligible cars are basically the first generation Formula Ford (Vintage Formula Ford) cars generally fitted with

     front radiators, outboard suspension, and brakes.

​

2.0 Eligibility

a.  The following commercially constructed cars are eligible.

b.  Any chassis not listed must petition for eligibility before being included.

 

Alexis 14 (1968) 15 (1969) 18 (1970) 18B (1971) 22 (1972)

Beach MKII (1969-70)

Bobsy (1969)

Bowin P4/P4A (1969-71) P6 (1972)

Caldwell D9 (1969) D9B (1970-71)

Crossle 16F (1968-69) 20F (1971-72)

Dulon LD4 (1967) LD4B (1968) LD4C (1969) LD9 (1970-72)

Elden PH6 (1969) PH8 (1970-72) PH10 (1972)

Elfin 600 (1969-72)

Forsgrini MK12 (1968-69)

Ginetta G18 (1969-70) G18B (1971)

Hawke DL2 (1969) DL2A (1970) DL2B (1971) DL9 (1972) DL9A (1972)

Ladybird MK8 (1968) MK9 (1969)

Legrand MK10 (1969-72)

Lola T200 (1970) T202 (1971) T204 (1972)

Lotus 51 (1967) 51B (1968) 51C (1969) 59 (1969-70) 61M (1970-72) 61MX (1972) 69 (1971-72)

Macon MR7B (1969) MR8 (1969-70) MR8B (1971)

March 708, 709 (1970) 718, 719 (1971) 729 (1972)

Mallock U2 MK9 (1969-70) U2MK9B (1971) U2MK9DD (1969-71) Mcnamara FFA (1970)

Merlyn MK11 (1968) MK11A (1969) MK17 (1970) MK17A (1971) MK20

(1971) MK20A (1972)

Mirage MK5 (1970)

Mistrale (1969-70)

Nike MK4 (1968-69) MK6 (1970)

MK10 (1971-72)

Royale RP2 (1969) RP3 (1970) RP3A (1971-72) RP16 (1972)

Tecno FF (1970)

Titan MK4 (1969) MK5 (1969) MK6 (1970) MK6A (1971) MK6B (1972) MK6C (1973)

Winkleman WDF1 (1969) WDF2 (1970) WDF3 (1971) WDF4 (1972)

​​

3.0 Chassis
a.  The chassis shall be of tubular steel construction with no stress bearing panels except the undertray, front

     bulkhead, and aft bulkhead/ firewall. 
b.  A stress-bearing panel is a panel that is riveted with less than 6” rivet spacing, bonded, or welded between

     chassis tubes or bulkheads. The curvature of the undertray shall not exceed one inch. 
c.  The tubes may transport liquid (oil or water). The addition of external tubes to carry water and oil is allowable. 
d.  The use of honeycomb and composite (carbon fiber, kevlar, etc) materials are prohibited.
e.  Frame modification in accordance with SCCA “General Competition Rules” (GCR) for 1979, or SCCA “Vintage”

     GCR, Appendix Z, regarding roll bar structure, is approved.  
f.  The addition of safety-related tubing and panels per section VI 3.0, 4.0 (side impact bars, roll hoops and braces,

    etc) is allowed but not required for Historic Ford. 
 

4.0 Body
a.  Body work must be run as originally fitted or as modified in period (pre 1973). 
b.  All body panels originally supplied with the model, with the exception of the engine undertray, must be used.

     They must be the original shape. 
c.  No part of the frame or body shall project beyond a plane connecting the vertical centerlines of the front and rear

     tires. 
d.  No skid plate shall extend beyond the bodywork, acting as a “down force device” or air splitter. 
e.  The driver’s seat must be capable of being entered without the removal or manipulation of any part or panel. 
f.   Wings (airfoils) are prohibited. 
g.  Rear spoilers in the form of raised surfaces, continuous with the body surface, and not wider than the body

     surface are allowable if fitted in period. 
h.  Advanced composite (carbon fiber, kevlar, etc) materials are prohibited. 
i.   The use of alternate bodywork is prohibited unless documentation of use in period can be verified.

​

5.0. Suspension And Running Gear
a.  Except as noted, all components shall be of ferrous material with the exception of hub adapters, rear hub

     carriers and bushings.  
b.  Shock absorbers are free except that they shall not be more than two-way adjustable and shall not have remote

     reservoirs. Aluminum bodied shocks are allowed.  
c.  Aluminum Hubs are not allowed. 
d.  Wheel spacers shall not exceed 1.5.”
e.  Rubber Donuts must be used on rear half-shafts. Exception will be granted to Royale RP-16 use of CV Joints, as

     well as to Historic cars where owner demonstrates conversion to CV joints prior to the modern era (1982 or

     later). 
f.  For safety, replacement of Metalastik drive donuts with BMW-type is approved.  Approved manufacturers/vendors

    are BMW 26117511454, Volvo 1220843 and Febi 04435. Other vendors are not approved. Sound engineering

    practices must be observed.
g.  Donut centering devices, though not original, are highly recommended.  
h.  The replacement of “metalastic” and plastic type bushings with spherical type is not prohibited. 

​

6.0 Original Specifications
a.  Must compete in the identical specification as manufactured. Updates and modifications, however "period" they

     might appear, are specifically prohibited. Relocation of suspension pickup points, alteration of wheelbase or track

     are examples of prohibited modifications.  
b.  The car must be restored to the original period specs, unless otherwise approved in writing.

​

7.0 Wheels 
a.  Historic Ford - Wheels shall be 13" pressed steel disc type with a maximum width of 5.5".  Wheels must be made

     of steel, but the offset may be altered.
b.  Any Historic Ford running non-steel wheels will be scored as a Club Ford.

 

8.0 Brakes
a.  See III. 5.0 for requirements.
b.  The addition of cockpit adjustable brakes bias systems is prohibited unless it can be proven to be period

     authentic on any Historic Ford.
 

V. CLUB FORMULA FORD REGULATIONS

1.0 Definition

a.  Eligible cars are basically the 2nd generation Formula Ford (Club Ford) cars campaigned in 1973 through 1981.

 b.  They are 1981 or older “second generation” designs with outboard suspension (shocks) on at least one chassis

     end.

 

2.0 Eligibility

a.  The following commercially constructed cars are eligible.

b.  Any chassis not listed must petition for eligibility before being included.

​

Alexis – MK23, MK 24, MK24B ADF – through 1981

Caldwell – DL15FF (also a few were made as DL9 in 1975) Crossle – 25F/30F/32F/35F/45F – 1976 to 1981

Dulon – MP15/17/19/21

Eagle – (Dan Gurney) – DGF

Elden – PRH10, PRH17, PRH19, PRH20, HD24

Elfin – 620

Gemini – 81C

Hawke – DL11, DL15, DL17, DL19

Hermes – 16/79, 16/80

Huron – FP2

HR2760

Image – FF2/FF2B/FF3/FF4/FF5

Javelin – JL2/JL5

Legrand – MK13/13B/21/27

Lola – T340/T342/T440/T540

Merlyn – MK24/25/28/29), MK-30 (1976),MK-31(1978)

PRS –  RH01, RH02, 81F

Reynard – 73F/76F/77F/78F

Rostron – RT 77/78

Rowland – 1975/76 RP, RP24-77, RP26-78

Royale – RP21/RP24/RP26/RP29

Sark 2

Sparton – FF78

Titan – MK8/9

Tiga FF75/FF76/FF78/FF79/FF80/FF81

Van Diemen – FA 73/74/76/78/79/80/81

Viking – NONE – 1st prototypes 1979 but 1st customer car delivered in 1982

Winkelman – became Nomad-Palliser – KHF/1 (WDF4), KHF/2 (WDF5/WDF6)

Zink – Z-10, Z-16

Zeus – FF81 (1981)

​

3.0. Chassis/Frame
a.  The chassis is defined as the frame. It shall be a steel space frame. Monocoque-type structures are prohibited. 
b.  Sheet material affixed to the frame by welding, bonding, or riveting, or by bolts or screws which are six (6) inch

     centers are defined as stress- bearing panels.
c.  The undertray, for safety reasons, shall be a stress-bearing panel. Its curvature shall not exceed one (1) inch. 
d.  The mountings for brake and clutch pedals and cylinders, and for the instrument panel and the bulkhead (panel)       behind the driver may be stress-bearing. No other stress-bearing panels are permitted.
e.  Brackets for mounting components, such as the engine, transmission, suspension pick-ups, instruments, clutch,

     and brake components, and body panels may be non-ferrous, of any shape, and fastened to the frame in any

     manner. Gussets are defined as of steel, fastened to a maximum of two (2) members, and are specifically

     permitted.
f.   The firewall portion of the bulkhead (panel) shall extend the full width of the cockpit and be as high as the top of

     the carburetor. Forward facing air ducts may be installed for the purpose of delivering air directly to the engine

     area. Air duct openings may be located within the cockpit provided the firewall is extended to prevent flame and

     debris from reaching the driver. (Any shape may be used to form firewall extension.) All firewall inlets shall

     prohibit passage of flame and debris.
g.  The chassis tubes may transport liquid (oil or water). The addition of external tubes to carry water and oil is

     allowable. 
h.  The use of honeycomb and composite (carbon fiber, Kevlar, etc.) materials are prohibited.
i.  The addition of safety-related tubing and panels per section VI 3.0, 4.0 (side impact bars, roll hoops and braces,

     etc.) is allowed but not required.

​

4.0 Suspension and Running Gear
a.  Suspension is defined as the system of springs, shock absorbers, A-arms, links, etc., supporting the vehicle on

     its axles. Sway bars, sway bar links, steering rack housings, steering links, etc., are not classified as suspension

     or running gear for this application.
b.  All components shall be of steel, with the exception of hubs, hub adapters, rear hub carriers, and bushings. Front

     hub carrier material shall be of steel or aluminum alloy. The materials for front and rear hub carriers on cars

     manufactured after January 1, 1983 will be only steel or aluminum alloy.
c.  Springs: steel only, titanium is prohibited.
d.  Shock absorbers: Design: Unrestricted. Casing Material: Steel or aluminum alloy. 
e.  All components which are not defined as chassis/frame or suspension or running gear are unrestricted, unless

     otherwise restricted by these rules. Titanium is prohibited.

​

5.0 Body
1.  Definition of Bodywork Internally: All visible parts of the passenger compartment. 
a.  The bodywork opening giving access to the cockpit shall have the following minimal dimensions: Length: 60cm

     (23.622 inches) Width: 45cm (17.72 inches) This width extends over a length of 30cm (11.811 inches) minimum.

     This minimal rectangular opening may exist anywhere forward of the firewall. Forward facing roll bar/ cage

     bracing and required padding will not be considered in these dimensions. 
b.  The driver’s seat shall be capable of being entered without the manipulation or removal of any part or panel.
c.  Bodywork, including fuel tanks, shall not exceed a maximum width of 95cm (37.4 inches).
d.  No part of the bodywork and aerodynamic devices shall exceed the height of a horizontal plane 90cm (35.4

     inches) above the ground. The safety roll bar/roll cage and engine air box are not included in this height

     restriction. Measurements are to be made in any condition, driver on board.
e.  No part of the bodywork shall extend more than 100cm (39 inches) behind the centerline of the rear axles.
f.   Any specific part of the car which has an aerodynamic influence on the stability of the vehicle shall be firmly fixed

     with no provisions for adjustment to vary downforce. 
g.  Side-mounted radiators (behind the front wheels) may extend beyond the 95cm (37.4 inches) limitation, but not

     beyond a vertical plane passing through the centerlines of the front and rear tires. Any portion of a radiator that

     extends beyond the 95cm (37.4 inches) limitation cannot be covered with any type of shrouding. Radiators

     mounted in front of the front wheels are considered front mounted and cannot exceed the 95cm (37.4 inches)

     limitation.
h.  Wings and other airfoil devices which have the principal effect of creating aerodynamic down-thrust are

     prohibited. Airfoil: Any device or part of a car (excepting normal and conventionally styled bodywork) which has a

     principal effect of creating aerodynamic downthrust. Within this definition may be included forward facing gaps or

     openings in the bodywork, but shall not include spoilers in the form of raised surfaces, continuous with the body

     surface, and not wider than the body surface.
i.  It is the intent of these rules to minimize the use of “ground effects” to achieve aerodynamic down-force on the

     vehicle. Thus, for the full width of the body between the front and rear axles, the lower surface (surface licked by

     the air-stream) shall not exceed 2.54cm (1 inch) deviation from the horizontal in any longitudinal section through

     that surface. (This is not to be interpreted as requiring a floor pan beneath the motor, transaxle, transmission, or

     final drive housing.) No aerodynamic devices (e.g., skirts, body sides, etc.) may extend more than 1cm (0.394

     inches) below the lower surface of the tub or chassis floor to the rear of the front axle. Seat buckets or other

     protrusions shall not circumvent this rule. It is not permitted to duct air through any part of the bodywork for the

     purpose of providing aerodynamic downforce on the car. All ducted air for heat exchangers (water/oil) shall pass

     through those heat exchangers.

​

6.0 Original Specifications
a.  Club Ford cars must compete in the specification as manufactured and raced. Updates and modifications which

     were made during the life of the car to improve its competitiveness and safety are permitted.  However, the racer,

     if challenged, must be able to demonstrate that these changes were in compliance with the SCCA GCR’s in

     effect during its racing history.

​

7.0 Brakes
a.  See III. 5.0 for requirements.
b.  The addition of cockpit adjustable brakes bias systems is allowed on Club Fords.
 

VI. POST-CLUB FORMULA FORD (PCF) REGULATIONS

1.0 Definition

a.  Eligible cars: Third-generation raced after the 1981 season using front and rear inboard suspension and vertical

     dampers not activated by bell cranks. 

b.  Specific list of eligible chassis. Other post-1981 cars may be accepted at the sole discretion of the FFCS

     Executive Committee.

c.  The PCF class cars are required to meet the 2015 SCCA FF GCR preparation rules, shown below, with the

     exception of tire and weight requirements as listed in the general rules at the beginning of this document.

d.  For Post-Club cars built before January 1st 1986 see Section 4.0

​

2.0 Eligibility

a.  The following commercially constructed cars are known to be eligible.

b.  Any chassis not listed must petition for eligibility before being included.

 

Chevron B67

Crossle 50F/55F/60F/65F/67F/70F/71F

Lola T640/T642/T644

PRS 82F

Reynard FF82/FF83/FF84/FF87

Royale RP31/RP33/RP36

Van Diemen RF82/RF83/RF84

Zink/Citation Z16 (inboard rear)

Viking 82/83

​​

3.0 Cars Registered Prior To 1/1/86
The following specifications are for cars registered prior to January 1, 1986 and for Technical Inspection only. No cars are to be built to these specifications as of January 1, 1986.

​

3.1. Chassis/Frame
a.  The chassis is defined as the frame. It shall be a steel space frame. Monocoque-type structures are prohibited. 
b.  Sheet material affixed to the frame by welding, bonding, or riveting, or by bolts or screws which are six (6) inch

     centers are defined as stress- bearing panels.
c.  The undertray, for safety reasons, shall be a stress-bearing panel. Its curvature shall not exceed one (1) inch. 
d.  The mountings for brake and clutch pedals and cylinders, and for the instrument panel and the bulkhead (panel)

     behind the driver may be stress-bearing. No other stress-bearing panels are permitted.
e.  Brackets for mounting components, such as the engine, transmission, suspension pick-ups, instruments, clutch,

     and brake components, and body panels may be non-ferrous, of any shape, and fastened to the frame in any

     manner. Gussets are defined as of steel, fastened to a maximum of two (2) members, and are specifically

     permitted.
f.   The firewall portion of the bulkhead (panel) shall extend the full width of the cockpit and be as high as the top of

     the carburetor. Forward facing air ducts may be installed for the purpose of delivering air directly to the engine

     area. Air duct openings may be located within the cockpit provided the firewall is extended to prevent flame and

     debris from reaching the driver. (Any shape may be used to form firewall extension.) All firewall inlets shall

     prohibit passage of flame and debris.

 

3.2. Suspension and Running Gear
a.  Suspension is defined as the system of springs, shock absorbers, A-arms, links, etc., supporting the vehicle on

     its axles. Sway bars, sway bar links, steering rack housings, steering links, etc., are not classified as suspension

     or running gear for this application.
b.  All components shall be of steel, with the exception of hubs, hub adapters, rear hub carriers, and bushings. Front

     hub carrier material shall be of steel or aluminum alloy. The materials for front and rear hub carriers on cars

     manufactured after January 1, 1983 will be only steel or aluminum alloy.
c.  Springs: steel only, titanium is prohibited.
d.  Shock absorbers: Design: Unrestricted. Casing Material: Steel or aluminum alloy. 
e.  All components which are not defined as chassis/frame or suspension or running gear are unrestricted, unless

     otherwise restricted by these rules. Titanium is prohibited.

​

3.3. Body
1.  Definition of Bodywork Internally: All visible parts of the passenger compartment. 
a.  The bodywork opening giving access to the cockpit shall have the following minimal dimensions: Length: 60cm

     (23.622 inches) Width: 45cm (17.72 inches) This width extends over a length of 30cm (11.811 inches) minimum.

     This minimal rectangular opening may exist anywhere forward of the firewall. Forward facing roll bar/ cage

     bracing and required padding will not be considered in these dimensions. 
b.  The driver’s seat shall be capable of being entered without the manipulation or removal of any part or panel.
c.  Bodywork, including fuel tanks, shall not exceed a maximum width of 95cm (37.4 inches).
d.  No part of the bodywork and aerodynamic devices shall exceed the height of a horizontal plane 90cm (35.4

     inches) above the ground. The safety roll bar/roll cage and engine air box are not included in this height

     restriction. Measurements are to be made in any condition, driver on board.
e.  No part of the bodywork shall extend more than 100cm (39 inches) behind the centerline of the rear axles.
f.   Any specific part of the car which has an aerodynamic influence on the stability of the vehicle shall be firmly fixed

     with no provisions for adjustment to vary downforce. 
g.  Side-mounted radiators (behind the front wheels) may extend beyond the 95cm (37.4 inches) limitation, but not

     beyond a vertical plane passing through the centerlines of the front and rear tires. Any portion of a radiator that

     extends beyond the 95cm (37.4 inches) limitation cannot be covered with any type of shrouding. Radiators

     mounted in front of the front wheels are considered front mounted and cannot exceed the 95cm (37.4 inches)

     limitation.
h.  Wings and other airfoil devices which have the principal effect of creating aerodynamic down-thrust are

     prohibited. Airfoil: Any device or part of a car (excepting normal and conventionally styled bodywork) which has a

     principal effect of creating aerodynamic downthrust. Within this definition may be included forward facing gaps or

     openings in the bodywork, but shall not include spoilers in the form of raised surfaces, continuous with the body

     surface, and not wider than the body surface.
i.  It is the intent of these rules to minimize the use of “ground effects” to achieve aerodynamic down-force on the

     vehicle. Thus, for the full width of the body between the front and rear axles, the lower surface (surface licked by

     the air-stream) shall not exceed 2.54cm (1 inch) deviation from the horizontal in any longitudinal section through

     that surface. (This is not to be interpreted as requiring a floor pan beneath the motor, transaxle, transmission, or

     final drive housing.) No aerodynamic devices (e.g., skirts, body sides, etc.) may extend more than 1cm (0.394

      inches) below the lower surface of the tub or chassis floor to the rear of the front axle. Seat buckets or other

     protrusions shall not circumvent this rule. It is not permitted to duct air through any part of the bodywork for the

     purpose of providing aerodynamic downforce on the car. All ducted air for heat exchangers (water/oil) shall pass

     through those heat exchangers.

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4.0 Cars built on or after 1/1/86
Formula Ford cars built and registered on or after January 1, 1986 shall meets the following specifications.

 

4.1 Chassis / Frame 
a.  The chassis shall be of steel space frame construction. Monocoque- type structures are prohibited. Stabilized

     (honeycomb) or composite (carbon fiber or Kevlar) materials are not permitted, except as specifically authorized

     within these rules. 
b.  Forward-facing braces protecting the driver’s legs and feet shall extend from the front roll hoop to the front

     bulkhead. (The front bulkhead is defined as the furthest forward transverse section of the main frame.) 
c.  The soles of the driver’s feet shall not extend beyond the front edge of the wheel rims (in normal position; i.e.,

     pedals not depressed) and shall remain behind the front bulkhead. 
d.  The lower main frame rails shall be a minimum of twenty-five (25) centimeters (9.84”) apart (inside dimension)

     from the front bulkhead to the rear roll hoop.
e.  The area between the upper and lower main frame tubes from the front roll hoop bulkhead to the rear roll

     hoop bulkhead shall be protected by one of the following methods to prevent the intrusion of objects into the

     cockpit.
1. Panel(s), minimum of either .060” heat treated aluminum (6061-T6 or equivalent) or eighteen (18) gauge

    steel, attached outside of the main frame tubes.
2. Reinforced body - at minimum, consisting of a double layer, five (5) oz., bi- directional, laminated Kevlar

    material incorporated into the body which shall be securely fastened to the frame.

For either method, fasteners shall be no closer than six (6) inch centers (no stress- bearing panels). 

The material used for the chassis braces in this area shall be at least equivalent to the roll hoop brace material.

f.  A stress-bearing floor pan/undertray, minimum of .060” heat treated aluminum or eighteen (18) gauge steel, is

     required; at a minimum this shall extend from the front bulkhead to the rear roll hoop bulkhead. Its curvature shall

     not exceed one inch. 
g.  Sheet materials attached to the frame by welding, bonding, or by rivets or threaded fasteners which are located

     closer than six (6) inch centers, are defined as stress- bearing panels. Composite or stabilized materials shall

     not be used for stress-bearing panels. 
h.  The mountings for brake and clutch pedals and cylinders (front bulkhead), instruments, (front roll hoop

     bulkhead), and rear roll hoop bulkhead (behind the driver) may also be stress-bearing panels. No other stress-

     bearing panels are permitted. 
i.  The firewall portion of the rear roll hoop bulkhead (panel) shall extend the full width of the cockpit and be at least

     equal to the top of the carburetor in vertical height. Forward facing air ducts may be installed for the purpose of

     delivering air directly to the engine area. Air duct openings may be located within the cockpit provided the

     firewall is extended to prevent flame and debris from reaching the driver. (Any shape may be used to form

     firewall extension.) All firewall inlets shall prohibit passage of flame and debris. 
j.  Brackets for mounting components, such as the engine, transmission, suspension pickups, instruments, clutch

     and brake components, and body panels may be nonferrous, of any shape, and fastened to the frame in any

     manner.

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4.2. Suspension
a.  Suspension is defined as the system of springs, shock absorbers, control arms, links, etc., supporting the

     vehicle on its axles. Sway bars, sway bar links, steering components, etc., are not classified as suspension for

     this discussion. 
b.  All suspension components shall be of steel or ferrous material, with the exception of hubs, hub adapters, hub

     carriers, bell cranks, pivot blocks and bushings. Front and rear hub carriers shall be only steel or aluminum alloy

     for cars manufactured after January 1, 1983.
c.  Springs shall be steel only.
d.  Control arms and all associated items which attach directly to the chassis members shall be boxed in or

     captured to prevent intrusion into the cockpit.
e.  Shock absorbers: Design - unrestricted; Casing Material steel or aluminum alloy. 
f.  All components which are not defined as chassis/frame or suspension are unrestricted, unless otherwise

     restricted by these rules or the GCR.
g.  Titanium is prohibited.
h.  It is not permitted to attach spoilers, fairings, or other devices which may exert downforce to the movable

     suspension members. If the suspension member is of streamline or airfoil cross section, it shall be symmetrical

     about its horizontal axis.
i.  Brake lines may be attached to the suspension.

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4.3. Bodywork
a. The bodywork opening giving access to the cockpit shall have the following minimal dimensions:

1.  Length: 60cm (23.622 inches)
2.  Width: 45cm (17.717 inches) This width extends over a length of 30cm (11.811 inches) minimum. This

     minimal rectangular opening may exist anywhere forward of the bracing, and required padding will not be

     considered in these dimensions.

b.  The driver’s seat shall be capable of being entered without the manipulation or removal of any part or panel.
c.  Bodywork (including fuel tanks) shall not exceed a maximum width of 95cm (37.44 inches). 
d.  No part of the bodywork, rear spoiler, or exhaust system shall extend more than 100cm (39 inches) behind the

     centerline of the rear axle.
e.  Bodywork shall not increase in width behind the centerline of the rear axle in any horizontal section. 
f.   There shall be no forward facing gaps or openings in the bodywork with the exception of those necessary for

     engine cooling, engine air inlet, shock, or brake cooling. 
g.  All bodywork shall be firmly attached to the chassis. 
h.  Wings and other airfoil devices which create aerodynamic downforce are prohibited. 
i.   No extension of the undertray or attached components for the purpose of downforce or ground effects are

     permitted. 
j.  Any part of the car which has an influence on the aerodynamic stability of the vehicle shall be firmly attached

     with no provisions for adjustment to vary downforce, except that a single rear spoiler, which may be capable of

     adjustment, is permitted. Cockpit adjustment is not permitted. This spoiler shall be no wider than the surface to

     which it is attached, and there shall be no gap between the spoiler and the body surface to which it is attached.
k.  No part of the bodywork or rear spoiler shall exceed the height of a horizontal plane 90cm (35.4 inches) above

     the ground, with the car as qualified or raced, with driver aboard. The safety roll bar/roll cage and engine air box

     are not included in this height restriction.
e.  It is the intent of these rules to minimize the use of “ground effects” to achieve aerodynamic downforce on the

     vehicle. Thus, for the full width of the body between the front and rear axles, the lower surface (surface licked by

     the airstream) shall not exceed 2.54cm (1 inch) deviation from the horizontal in any longitudinal section through

     that surface. (This is not to be interpreted as requiring a floor pan beneath the motor, transaxle, transmission, or

     final drive housing.) Diffuser undertrays or venturi tunnels are prohibited. No aerodynamic devices (e.g., skirts,

     body sides, etc.) may extend more than 1cm (0.394 inches) below the lower surface of the floor pan to the rear

     of the front axle. Seat buckets or other protrusions shall not circumvent this rule. It is not permitted to duct air

     through any part of the bodywork for the purpose of providing aerodynamic downforce on the car. All ducted air

     for heat exchangers (water/oil) shall pass through those heat exchangers.
f.  Carbon fiber is not permitted.
 

Applicable to all 3 classes except as listed above in General Rules Applicable to All Three Classes (re: weight and tires) and below, as noted in Historic and Club Ford sections. For Post-Club cars built before January 1st 1986 substitute D.12 for D.6, D.7, and D.8 only.

 

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