The Official MotorSport New Zealand Manual

Schedule T&C

Schedule T&C – Modified Classic Racing Cars

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Part Five – Schedule T&C

Contents Last Updated: 5 November 2021

Article 1 Identity Classification
Article 2 Interpretations and Definitions
Article 3 Group 1 – Sports and GT Cars up to 31 December 1977. and,
Group 2 – Production Saloon Cars up to 31 December 1977:
Group 3 – Sports and GT Cars Post 31 December 1977 and over twenty(20) years old
Group 4 – Production Saloon Cars Post 31 December 1977 and over twenty(20) years old

Note: Text changes from the previous issue of this Schedule are highlighted such. Text changes for grammatical and/or formatting reasons are not highlighted.

Thoroughbred & Classic Car Regulations

These rules apply to all saloons, sports and GT with a minimum production run of one-hundred(100) identical units and covers cars over twenty(20) years old and not covered by Appendix Six Schedule K or FIA Appendix K.
Objectives: This Schedule is designed to provide a set of regulations for the use of period production based Sports, Grand Touring, and Saloon Cars in sporting competition while maintaining the philosophy of the Historic and Classic movement.
Where appropriate, the regulations have been formulated to preserve period specifications by preventing the application of technology that was unavailable for the period depicted.
These regulations define the ONLY ALLOWABLE changes in each vehicle raced, which differ from the standard model variant the vehicle represents.
Identity Classification:
Refer to Part Three of this Appendix for details on the Certificate of Description and for details on vehicle classification.
Note: The onus of proof relating to the appropriate vehicle Certificate of Description classification rests entirely with the competitor.
The date assigned to a vehicle by a COD or from corroborated information supplied by the competitor, representing the vehicle’s owner, will be the actual year of commencement of manufacture of that model.
Once classified, cars may only be re-classified by order of MotorSport NZ. It is the entrant’s responsibility to prove the eligibility of a car’s specifications as entered on the Certificate of Description.
Any appeal or enquiry regarding classification status shall be referred to MotorSport NZ.
Interpretations and Definitions: In addition to the interpretations detailed in the National Sporting Code Article 2 and in Section One Article 2.1 of Schedule K, the following apply to this schedule;
Note: These definitions are to be read in conjunction with these rules.
“Appearance suitable” means appropriate to or available in the period or era that the car depicts, and
“Era” means the years (period) during which a vehicle model and/or its components were used actively in motorsport competition, and
“Exterior Trim” means all ornamentation, often chrome or contrasting colour, which may include bumpers, over-riders, grills, light surrounds, strips and badges as standard fitment, and
“Grand Touring” or “GT” means a performance derived two(2) door closed vehicle with two(2) seats or 2+2 seating, and
“Homologation” is the term given to the official certification made by the FIA that a specified minimum number of a specific model and associated homologated parts have been made on series production terms, and
“Interior Trim” includes, but not limited to, the door and panel trims, parcel shelf, rear seat, dash, upholstery, knobs and ceiling trim, but excludes flooring vinyl, carpets, and original fitment front seats. Floor coverings and ceiling trim are non-critical items, and
“Make” means the part(s) produced within that manufacturer’s model range during the production life of that model or model variant. A change in model is determined by a change in model number/classification instigated by the manufacturer, and
“Model” means the vehicles and components thereof produced within a single model number or classification within the manufacturers model range, and
“Period” means the era (years) during which a vehicle model and/or its components were first used actively in Motorsport Competition, and
“Period Variations” means variations carried out on that vehicle model, that were variations available in the era during which a vehicle model and/or its components were first used actively in motorsport competition, and
“Saloon” means a two(2) or four(4) door vehicle not falling into either the Sports or GT categories including the convertible variations of same, and
“Sports Car” means a two(2) seat open vehicle and the fixed head variations of the same, and
“Standard” means a vehicle identifiable as belonging to a production series, with a minimum model run of 100 identical units, distinguishable by external general lines of the bodywork and identical mechanical construction of the engine, transmission and suspension to the wheels, and
“Standard Material Type” means of the same construction and composition as available on the standard model, and
Note: An application can be made to the Historic Advisory Commission via it’s Chairperson, when the applicant deems that are particular part of interior or exterior trim is no longer available, or viable to be used in competition. The Commission will review the application and accompanying proof of reason and will determine if derogation is granted. This will then be noted in the vehicle’s COD. Note that the vehicle must have a COD (Certificate of Description).

(2) All other modifications are strictly prohibited except as specified elsewhere in this Schedule.(2) All other modifications (including period, homologated) are strictly prohibited except as specified elsewhere in this Schedule.


Group 1:
Sports and GT Cars up to 31 December 1977
Group 2:
Production Saloon Cars up to 31 December 1977
Group 3:
Sports and GT Cars Post 31 December 1977 and over twenty(20) years old
Group 4:
Production Saloon Cars Post 31 December 1977 and over twenty(20) years old
Important Notes: The following regulations have been formulated to preserve period specifications by preventing the application of technology that is inappropriate for the period depicted. (Refer Article 2. Interpretations and Definitions). The objectives stated at the start of this Schedule should be considered in relation with all of the following Articles.
Note: Each Article is numbered on the left side of the table. Regulations pertaining to specific Groups can be found by reading across the page below the Group heading.
(1) A vehicle may be modified to utilize the period variations within the manufacturer’s model body shell. Minor alterations to facilitate fitment of safety items is allowed. The boot floor may be replaced with a rigid material (from period) and modified, to allow fitment of a fuel cell.
(3) The onus of providing proof of eligibility remains the responsibility of the competitor.
Note: It is the responsibility of the competitor to be able to show conclusively that the vehicle contains only specifications of its original build and modifications that pertain to that particular model in the manufacturer’s range.
(3) The onus of providing proof of eligibility remains the responsibility of the competitor.
(4) Scrutineering audits: These will be conducted to the requirements of Appendix Six Schedule AA or Appendix Two Schedule A where appropriate and accompanied by a valid COD.
The vehicle shall be smartly maintained and have all exterior trim in place. It must retain bumpers if originally fitted. All panels, bumpers, mouldings, spoilers etc. must be made of the original materials as per the STANDARD series Production vehicle. eg; steel panels must be retained if originally fitted. Period modifications are permissible.
(1) Only rear wings (aerofoil) which were available for the car in period may be fitted. These must be made of materials from that period. ie; no Kevlar.
(2) Any/all modifications must be in period (refer definitions).
(1) Floor coverings and ceiling trim may be removed.
(2) Front seats may be replaced with recognised competition seats.
(3) Seatbelts must comply with Appendix Two Schedule A or Appendix Six Schedule AA as appropriate for competition.
(4) Solid wood-rimmed steering wheels are prohibited, even when they are original fitment. The steering wheel may be replaced with a sports or competition wheel.
(5) Any non-visible devices such as heater and fan may be removed or substituted. No modification from standard permissible
Note: refer to “Interior Trim” above.
(6) Interior/Door panels must be retained. ie; no open and uncovered door frame cavities or between door and frame. Minor interior items such as door storage pockets and underdash trays may be removed.
(7) If roll over protection is fitted, the headlining may be removed and the original dashboard modified to permit ease of installation of the roll structure.
Fitting of a laminated windscreen is strongly recommended. All other glazing may be substituted with alternative transparent material, but original fixing medium must be used including operating mechanisms. All glazing must to be a minimum of 5mm 4.5mm thick and in compliance with Appendix Two Schedule A. No modification from standard permissible.
(1) The standard chassis must retain full structural integrity, i.e. removal of any material or component which was originally designed as load-bearing is strictly prohibited.
(2) Addition of stiffening material and components is permitted.
(3) Transmission tunnels and inner guards to remain as standard. Tunnels may be modified for shifter/lever clearance only. Shifter must retain original position.
No modification from standard permissible
(1) Cylinder head(s) and block may be changed to one of the same make and model range and must be visually standard and be of standard material.
(2) All other componentry is free providing the original OE dimensions are respected. Turbo and supercharging are only allowed if standard, in which case the standard turbo(s) and/or supercharger must be retained.
(3) Computerised engine management systems are prohibited unless standard fitment.
(4) Overboring of cylinder blocks to maximum of 0.060″ is permitted. Removal of material from rotating or reciprocating parts for the purpose of balancing is permitted. Cylinder heads may be ported and polished.
Over boring of cylinder blocks to a maximum of +1.5mm (0.060”) and removal of material from rotating or reciprocating parts for the purpose of balancing is permitted. Cylinder heads may be ported and polished.Electronic engine management systems are permitted if originally fitted to the vehicle. Replacement systems are permitted providing they have the same functionality as the original.
The exhaust system is free provided that the maximum permitted decibel limit as specified in Appendix Two Schedule A is not exceeded.
Clutch, Gearbox, Overdrive (If any)
(1) Clutch and flywheel can be replaced. Gearbox and overdrive may be changed to another that was available in the same period (preferably from the same manufacturer) as the car depicts and must have the same number of forward ratios as standard.
(2) If an overdrive was originally fitted this may be included as one(1) extra gear ratio.
(3) Gear ratios may be substituted; sequential shift mechanisms are prohibited except where standard.
No modification from standard permissible.
May be changed provided the type of suspension is not affected. Ratios may be changed. Limited slip and locked differentials are permitted. No modification from standard permissible.
Original period componentry must be retained but may be modified, providing it still performs its original function. Additional components may be fitted as required providing in all cases the standard type of suspension and chassis mounting points (in their original position) are retained and used for their primary function. (1) The make, rate and dimensions of springs, shock absorbers and sway bars are free.
(2) Sway bars may be modified to allow adjustment of rate.
(3) Bushing material is free provided the original suspension arm requires no modification when fitting the bushing.
Brakes must be to period specification, and all disc and drum friction surfaces must be made from ferrous material. Monobloc and radial brakes are specifically not allowed. Cooling ducts may be fitted. Brake friction linings are free. The friction material of brake shoes, brake pads and clutch drive plates are free (refer to definitions). ABS braking system may be used.
Wheels must fit within the bodywork and they have a period appearance suitable for that model. A maximum of one inch(1”)(25mm) larger diameter from the standard wheel size used by the vehicle manufacturer in the period the car depicts may be used. No wheel to be larger than 15″. Wheels must fit within the bodywork. Standard wheels or wheels homologated in period are permitted.
Applicable to Group 1 and 2 only.
Only radial tyres with a road legal tread in New Zealand may be used. (ie. road tyres having 1.5mm minimum tread depth across 75% of the width of the tyre and around the entire circumference). Aspect ratio for radial tyres is restricted to 50% minimum. The use of semi-slick tyres with only radial grooves is specifically prohibited.

Alternative tread patterned Bias cross ply tyres conforming with the above tread depth and circumference specifications are approved.
1. Examples of Bias tyres are Dunlop CR65 or Hoosier vintage or TDR treaded tyres.
2. Not all DOT rated tyres are road legal
Only tyres applicable to the period of the vehicle and suitable for legal road use may be used. The aspect ratio shall be in accordance with and have an appearance appropriate to the period the car depicts.