It's really a matter of what you're going to use it for and what your engines operating range (rpm) is going to be most of the time. This has a lot to do with with your daily driving, transmittion type, and drive ratio in your axles. Bottom line is that a cam is the heart of an engine, and is engineered to perform within certain RPM ranges. <br><br>I own a 74, 302 @ .030 over bore, rebuilt stock heads and valves, edelbrock performer, edelbrock 600cfm, headers, DUI ignition, and a 3.50 axle ratio. Most of my driving is going to be at 3,500 rpm and below, so I wanted a cam that performs it best in the lower to mid ranges of the engine. I opted for a Melling high torque cam (MTF 1), which is designed to give you gobbs of low end punch, and good horse power improvements through the mid rpm ranges, but flattens out above 3,500 rpm.<br><br>Long explaination, but hope it gives you some info. If the person/company your buying a cam from doesn't ask you any of the specifics I mentioned above, they're just after a sale and really don't care. Find some one who knows their stuff, and they're steer you in the right direction.