Wehrs Machine carburetor spacer plate tuning system gives you the ability to change the amount of horsepower you want according to changing track conditions. Just like the restrictor plates we have seen Nascar use you can dial down the power as the track conditions deteriorate. You can adjust from wide open with no restriction down to a 1 in. restrictor plate which reduces power by 14%. These carburetor tuning spacers are available in 1 in. as well as a 2 in. version.