TThe lump has a polar moment of inertia of 10.07 m^2 kg. So your average airhead should produce a run of around 10 seconds in 4th gear. If successful at getting around 90hp at the back wheel of the salt racer then runs will need to be done in top gear. In which case, that 415kg wheel will be spinning at around 2600RPM. All this is theoretical. It’ll be interesting to finally see how close to reality my maths is!
Here’s a drawing of the wheel.