Okay, I think I've wrapped everything we've talked about into the proposed rules package on the previous page. To preclude compromising tube frame chassis' lower frame rails in the search for downforce, I added a line from the FF rules (2006 GCR, D.6.a) as "1" under Chassis. That leaves plenty of room for experimentation without compromising safety.
FORMULA 1000 PREPARATION RULE
Formula 1000 is a restricted class for single seat, open wheel racing cars as defined by these regulations.
A. Chassis: Monocoque or tubular chassis construction.
1. Tube frame chassis lower 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.
2. Engine oil or water tubes are not permitted within the cockpit.
3. Chassis of non-metallic composite construction shall be proven to meet FIA specifications for non-metallic composite chassis prior to being submitted to the SCCA for homologation. Contact the SCCA national office for a list of the relevant FIA specifications/SCCA requirements.
B. Bodywork and Airfoils: Maximum dimensions per Formula Continental rules.
1. No part of the suspended part of the car shall extend more than 1 cm (0.394 inches) below the plane forming the bottom of the tub or chassis.
C. Engines: Production 4-stroke motorcycle engines up to 4 cylinders are the only permitted engines.
1. Carburetion and fuel injection are unrestricted.
2. An SIR is required, based on engine displacement. See 2006 GCR page GTCS-40 for SIR rules.
a. Over 900cc and up to 1100cc – 25.0mm
b. Over 1100cc and up to 1300cc – 24.75mm
3. Lubrication system is unrestricted.
4. Cooling system is unrestricted.
D. Suspension: Carbon fiber and titanium suspension components are prohibited.
1. Springs: Steel only.
2. Shock Absorbers: Steel or aluminum alloy body only.
E. Brakes: Unrestricted, except that carbon brake rotors are prohibited.
F. Wheels and Tires: Unrestricted providing wheels are metal.
G. Transmission: The gearbox shall contain not more than six (6) forward gears.
1. The use of an automatically shifted gearbox is prohibited.
2. Electric and/or pneumatic assisted gear change mechanisms are permitted.
3. Rear wheel drive only is permitted.
4. Final drive ratio and gear ratios are unrestricted.
5. Differentials are unrestricted, except that electronically controlled differentials are prohibited.
6. A reverse gear is not required.
H. Weight: 900 lbs minimum as raced with driver.
1. Pre-1993 FC cars with motorcycle engines may compete at their 2005 GCR specification and weight.
Edit: Deleted the word 'horizontal' from B.1.