Hurricane engine torque

[Viper2000]

If you go down that path then the next thing to do is to start looking very closely at what the valves are actually doing when the engine is running; you may find that they aren't quite behaving as you expect.

You may also find that the valve springs become unhappy.

There may be some performance advantage to be had from new valves made out of superior materials, especially if you can save weight.

Of course, all of this stuff gets expensive rapidly, and so it's worthwhile to decide what price you're prepared to pay for say 0.01 s/lap. Then you can start analysing your options and rationally allocating budget.

Of course, for this to work really well you need a simulator so that you can investigate the way in which your driver will respond to car performance changes; you may find that changes in power or grip have surprising unintended consequences for the racing line that your driver elects to take around the track, which can either positively or negatively affect the overall lap time.

As with so many things in life, the job is never finished; eventually you just have to decide when to stop.