b.
c.
d.
e.
f.
It must be equipped with fixed seats for a Driver and one adult Passenger and have seat backs not less than 30.5cm measured from the uncompressed base seat cushions along the angle of the seat back.
The rearmost portion of the seats( without cushions) at this 30.5cm height must not be behind a line through the vertical axis of the rear hubs.
All Passenger handles must be of rigid construction securely anchored and neither flexible nor adjustable.
No handle must be capable of touching the ground in the event of a roll-over and all handles must be sited so that in the event of the car hitting a solid object the handles are protected from contact with the object by the chassis.
Rear mudguards must be of adequate strength to protect Driver and Passenger from wheels and tyres.
i.
ii.
Rear mudguards must cover the full length of the tyre in plan view at the top of the wheel and must extend outwards to within 5cm of the outside edge of the tyre wall. Front mudguards must cover the full width of the tyre over an arc of 90 ° and extend rearward to not more than 10 ° above the horizontal line through the front hub.
6. Engine 6.1. Only the following engines are permitted in Historic Class:
a. Ford Sidevalve. b.
BMC A Series up to 948cc c. Austin 7 d.
Reliant 600 / 700 / 750 OHV e. Reliant 750 Sidevalve.
6.1.1 Maximum of 60 thou overbore is permitted, the stoke must be standard and the camshaft and valves must be in original position.
6.2. Post Historic Class must use a period engine of up to 1650cc. 6.3. At least one period European Carburetor must be fitted and in operation 6.4. Forced induction is not permitted unless originally fitted to the vehicle. 6.5. Ignition systems must use a period distributor but the use of a contact breaker is not mandatory. 6.6. Ignition mapping or any form or engine management system is not permitted. 6.7. Electric Water Pumps and cooling fans are permitted. 6.8. The fitting of a generator is optional.
7. Gearbox 7.1. Historic Class Vehicles must be:
a.
Fitted with a gearbox from a series production car of period. the casing and gear ratios may not be modified other than the fitment of a Ford 100E input shaft to a Ford 8 gearbox.
8. Suspension
b. The gearbox must be bolted directly to the engine.
8.1. Historic Class Vehicles must use transverse leaf front suspension unless the vehicle was manufactured in period using coil over dampers with the lower mountings on or close to the king pins. Otherwise Vehicles must be fitted with period leaf or coil spring systems.
Motorsport UK National Competition Rules 2026 Edition 1
Chapter 17 Appendix 6- Technical Regulations- HST Formula 632