There have been a few variations mainly in the last couple of years but I’ll run through them.
1. 32mm tube F250 National Chassis (ICE). This has been produced in pretty much the same format from 2000 right up to present day. It’s a relatively stiff chassis that benefits from the use of soft tyres. From 2002 it had mountings that allowed 2 axle positions (Long and short wheelbase). Most run it in long wheelbase. Typically fitted with Honda CR250.
2. GasGas chassis. 30mm tube. This was basically the Maverick Div 1 (FE) chassis. The earlier versions kept the chassis mounted engine mount tags pointing away from each other. So to accommodate the shorter GasGas engine there was a long swan necked front engine mount which was not ideal. The wheelbase was 20mm longer than the 32mm F250 National chassis. A softer chassis which worked better with a slightly harder tyre. Later versions had the engine mount tags turned to point towards each other so using the same mounts that were used in the F250 National.
3. 30mm tube short wheelbase chassis. Basically exactly the same as the F250 National 32mm chassis, except for the tube size.
4. 30mm tube long wheelbase F250 National Chassis. Currently favourite with the quick guys.
Exactly the same as the current Div 1 chassis, but with engine mount tags to suit the shorter single cylinder engine.
All the above chassis can be fitted with a plain floortray or diffuser.
The later rear bumpers have tags to bolt up the rear of a diffuser, whereas you have to use zip ties or tubing clamps with the earlier bumper.
In the period from 2000 to 2014 there have been various styles of nosecone, drivers bubble. sidepods and rear wing. Most competitors seem to prefer either the 2010 or the current style bodywork. The latest bodywork is better with a diffuser.
Any specifics or pictures, just ask away.