When replacing the clutch, there are two avenues to choose from. Stick with an OE stock unit, or upgrade for an aftermarket performance clutch. If you plan to keep your car stock, there really is no need to upgrade to a performance clutch. Stock clutches, as you probably could imagine, are the least expensive. Stock units are available from a host of manufacturers. Ford and Exedy are two reputable sources for replacement OE units.
Now, if you plan on upgrading your ride (or already have) and are looking for a bit more ‘bite’, then consider an aftermarket performance clutch. Differences over stock clutches are many. To begin, performance clutches can support more horsepower and torque. How much more? Well that depends on the manufacturer, and specifically, the clutch. Manufacturers commonly market performance clutches in stages, or by numbers (100, 200, 300 etc). I.e, the next level up from a stock unit is a stage 1 clutch; an upgrade from stage 1 is stage 2 and so on and so forth. Sometimes they may even have levels between whole numbers (ex: stage 2, stage 2 , stage 3). Generally speaking, the difference between levels is the clutch lining material and spring/diaphragm force. As you move up clutch levels, horsepower and torque ratings increase, as does clutch stiffness during operation. Now, in the aftermarket world, particularly with clutches, there are a ton of players out there looking to make a sale. Between technical jargon and competitive pricing, sometimes it is quite hard to figure out which clutch will do the job and which is a lemon. Spec, Exedy, Ram and Ford Racing are four reputable companies that offer excellent performance clutches, available a la carte depending on what you need. The four companies all offer varying levels of performance and all include a release (throwout) bearing and alignment tool as part of the package (very important for install!). Which level to choose depends on what kind of horsepower that Ford smallblock is, or will be, creating.