really? you guys dont know why and why reeds spacers are used?
By placing the reed spacer between the reed cage and the engine you increase the crank case volume and by moving the reeds back further you move the power band lower. By placing the reed spacer between the reed cage and the carb manifold you move the carburetor back and this moves the power band higher up.
The overall HP stays the same. A spacer does nothing to add HP. It only takes the HP you have and moves it higher or lower depending on what you need or want it.