1973 and older sleds may compete, no reed or rotary valve engines allowed. This class is for HR port engines.
- 1973 and older chassis
- 1973 and older single cylinder engine only. Brand must match chassis.
- Over bore allowed
- Any type stock muffler, no expansion chambers or tuned exhaust allowed.
- No Reed or Rotary valves allowed
- Point Ignition only, no CDI allowed
- Float type carbs allowed / no flat slides
- HR port sleds may enter this class
- Studs allowed, max 3/8 above track lug
- Carbides allowed
- Any type or brand replacement track may be used, ¾ lug max.
- Suspensions may be interchanged up to model year 1978.
- Stock Drive clutch or Power Block / Comet 94C duster may be used.
- Stock Secondary clutch.
- Steel skis only.
- No adjustable handlebars.
- Seat must be stock appearing.
- Ski Spreaders allowed, 3 inch max.