[SCCA] Solo II Street Modified Category

This is an unofficial transcription of Section 18 of the 2003 SCCA National Solo Rules. (Copyright Sports Car Club of America 2003; all rights reserved;) It is believed to be correct, but any questions should be referred to the official rules as published by the SCCA. Order your own copy here.

Changes since the 2002 Rules are shown like this.
Further changes from FasTrack are shown like this.



  1. To serve as a membership recruitment and retention tool by providing a natural competition outlet for auto enthusiasts using streetable sport sedans equipped with drivetrain and suspension modifications that are beyond those allowed in the Street Prepared category.
  1. Street Mod (SM), a full National class for sedans/coupes as described below.
  2. Street Mod 2 (SM2), Regional optional class for two seat cars and selected sedans/coupes as describes below.  Supplemental class at 2003 National Tour and ProSolo NationalSeries events
  3. Regions are encouraged to use the basic Street Mod rules for a class or class(es) beyond that indicated below if they have a local demand. 
  1. STREET MOD (SM): All sedans/coupes (models which were originally equipped with a minimum of four seats, four factory seat belts, not sports car based).
    1. Sample Vehicles:
      • Chrysler: Neon, Stratus/Breeze
      • Ford: Contour, Escort, Probe, Mustang
      • General Motors: Cavalier, Sunfire, Camaro
      • Honda: Civic, Accord, Integra
      • Hyundai: Elantra, Tiburon
      • Mazda: Protege, MX-6, 626
      • Nissan: Altima, Sentra
      • Toyota: Celica, Corolla, Camry
      • VW: Golf, Jetta
    2. Sample Excluded Vehicles:
      • Porsche, all
      • Datsun Z car 2+2
      • Honda CRX
      • MGB GT
      • Triumph, all
  2. STREET MOD 2 (SM2): 
    1. All two seater cars, not excluded below.
    2. All SM eligible sedans/coupes excluded from SM for failure to meet weight and/or displacement limits.
    3. Excluded Vehicles: 


  1. All Street Touring modifications are allowed.
  2. All Street Prepared modifications are allowed.
  3. Section 15.6(Prepared Category, Brakes),  except for subsection 15.6.H.
  4. Drivetrain and related components (induction, ignition, fuel systems, etc.) are unrestricted except for the following limitations:
    1. Engine must be from the same manufacturer as the body (Toyota/Lexus, Nissan/Datsun, Honda/Acura, etc.) Badges that exist as marketing aliases for the manufacturer (Honda/Acura, Toyota/Lexus, Nissan/Datsun) will be recognized as equivalents.  Swaps involving makes related only at corporate level (e.g. Ford/Volvo, Renault/Nissan, Chrysler/Mercedes) are not recognized as equivalents.  Models produced as a joint venture between manufacturers may utilize any engine from any partners in the joint venture, provided that an engine from the desired manufacturer was a factory option in that particular model (e.g. Eagle Talon available originally with either a Mitsubishi or Chrysler engine, may use any motor from Chrysler or Mitsubishi).
    2. Maximum engine displacement:

    3. Must comply with section 3.6.6 (3.6.B? There is no 3.6.6) regarding fuel.
  5. Suspension components are unrestricted as long as they use the original attachment points.  Brakes are unrestricted.
  6. Subframe connectors are allowed, but each connector must be attached individually without any lateral components attaching the two longitudinal frame rails.  Subframe connectors may be bolted or welded
  7. The firewall, roof, doors, rear quarter panels, floor pan, trunk lid (if any) or rear hatch (if any) must remain stock.  Holes may be drilled to allow attachment of body kits, etc.  This specifically allows replacement hoods, fenders, wings, front & rear fascias, side skirts, and fender flares as per Section 14Body panels may be attached with removeable (e.g., Dzus) fasteners.
  8. Except as noted by these rules and the referenced rules, vehicles must be as originally delivered including all road going components such as lights, wipers, interior, heater, etc.
  9. Rear passenger seat(s) do(es) not need to be retained.
  10. Wings may only be attached to the rear deck/hatch area and may not extend more than six inches beyond the widest part of the bodywork on either side.
  11. Any minor modification, intended to allow or facilitate any allowed modification, is permitted as long as it does not provide any intrinsic performance benefit in and of itself, does not provide a weight reduction of more than 1 lb., and is not explicitly prohibited elsewhere within these rules.  This rule is intended to allow minor notching, bending, clearancing, grinding; the drilling of holes; affixing, relocating, or strengthening of brackets; removal of small parts, and similar operations performed in order to facilitate the installation of allowed parts or modifications.  Competitors are strongly cautioned to make the minimum amount of modification required to affix a given part, and not to make unduly tortured interpretations of this rule.  Modifications to the firewall in order to allow for increased engine setback, and any modification that changes the location of of a suspension pickup point, are explicitly forbiddden.


  1. Street Mod (SM)
    1. Up to 3.0L, naturally aspirated, OHC engines
      Up to 4.0L, naturally aspirated, pushrod engines
      1. FWD: 1800 pounds
      2. RWD: 2200 pounds
      3. AWD: 2400 pounds
    2. Up to 3.0L, forced induction, OHC engines
      Up to 4.0L, forced induction, pushrod engines
      1. FWD: 1900 pounds
      2. RWD: 2400 pounds
      3. AWD: 2600 pounds
    3. Up to 3.01 to 6.0L, naturally aspirated, OHC engines
      Up to 4.01 to 6.0L, naturally aspirated, pushrod engines
      Up to 1.5L, rotary engines, all
      1. FWD: 2000 pounds
      2. RWD: 2500 pounds
      3. AWD: 2700 pounds
  2. Street Mod 2 (SM2), two seat vehicles and underweight SM vehicles
    1. Up to 4.0L, naturally aspirated, OHC engines
      Up to 5.0L, naturally aspirated, pushrod engines
      1. FWD: 1500 pounds
      2. RWD: 1900 pounds
      3. AWD: 2100 pounds
    2. Up to 4.0L, forced induction, OHC engines
      Up to 5.0L, forced induction, pushrod engines
      1. FWD: 1600 pounds
      2. RWD: 2100 pounds
      3. AWD: 2300 pounds
    3. Up to 4.01 to 8.5.0L, naturally aspirated, OHC engines
      Up to 5.01 to 8.5L, naturally aspirated, pushrod engines
      Up to 3.0L, rotary engines, all
      1. FWD: 1700 pounds
      2. RWD: 2200 pounds
      3. AWD: 2400 pounds
  3. Street Mod 2 (SM2), over-displacement SM vehicles
    1. All types/displacements
      1. FWD: 2000 pounds
      2. RWD: 2500 pounds
      3. AWD: 2700 pounds

18.3. OTHER

  1. Due to the inherent creative nature of this category of classes and the resulting member questions about the intent and interpretation of the rules, the SEB will issue clarifying Tech Bulletins in SportsCar magazine on an as-needed basis.  Car constructors are cautioned against overly creative or tortured interpretations of these rules.  When in question, contact the SCCA National Office for a clarification.


...Jerry Mouton || jerry@moutons.org || Last modified 02/22/03