the fact is that even the best cam will work poorly with a crappy set of heads...not to sound dicky at all, but this is a really loaded question!!!you really need to know a little about the fundamentals of an engine before you can unbderstand the design of a cam...its lobe seperation angle, lift, duration, ramp profile, roller or non, mechanical or hydraulic...lol...there is a lot of info here to digest...basically, a cam in simplest form is a series of steel "ramps" that push open valves...all 4 stroke engines have cams...cams will completely change the way an engine performs...a shorter duration (like a 250)with mild lift will produce torque, and at low rpm...a longer duration( like a 292 duration) with a bigger lift will give torque at a later time and hp in a higher rpm.torque is a mathmatical function of horsepower and rpm...and after all of this, a piss poor cam with a fantastic sety of heads is gonna outperform a fantastic cam with piss poor heads...cams rely on compression ratio, intake runner length and volume, valve size, and many other things in order to function correctly, so your homework unfortunately just gained a few more subjects...lol...take everything i`ve just said lightly, as this isnt meant to hurt feelings, but just to inform...hope it helps...