In my experience with Carb'd CVH engines a performance camshaft will only really noticibly improve performance if used in conjunction with other mods (bike carbs/twin 40s, ported & polished head, bigger valves, 4 branch manifold, performance exhaust system, overbore etc). The benefits will obviously be less when installed in a stock engine. Lumpy idle is another side effect. Im not familiar with injected engines but they may benefit from a remap after installing the cam to get the best.