Yes and no, it all depends on what kind of carb your runnin and the size of the airfilter. Unless your comparing off the dyno its hard to tell. The increased surface area of the filter helps the air to pass easier through the air filter, on the other side on some carburators it causes turbulance causing a decrease in horsepower but gains or losses are small. If your really worried about a couple horsepower, slap it on a dyno and see what happens (personally, someone is going to throw rocks at me for this, but just get a bigger air filter if you want more hp). If not and your just want the cool factor, throw it on top and dont worry about it (you shouldn't feel a difference), worse come to worse you can always take it back.
