There sure are a lot of companies making serpentine belt pulley kits these days. Concept One Pulley Systems competes with CVF, Eddie Motorsports, March Performance, Billet Specialties, and Holley. That's only half of the brands on the market. The interesting thing is that an accessory drive system is relatively complex.  If you choose the wrong brand, you might end up making a costly mistake. Here are some factors to consider before choosing an accessory drive kit.   

Heavy-duty brackets - Full front and rear support

Accessory drive components are heavy. They are also under tremendous load.  A compact SD7 AC compressor weighs 10 pounds and has seven pistons that constantly punch back and forth. Additional load is created by belt tension. Unfortunately, many accessory drive systems use a single plate that supports only the front of the components. The lack of rear support places excessive stress on the single front bracket, which can cause it to flex and lead to stress cracks.  

Concept One systems feature front and rear brackets that fully support accessory drive components at both ends. This design eliminates the risk of flex-induced stress cracks that can occur with single-plate designs.

Completeness

A complete kit should include all necessary hardware, brackets, pulleys, accessories, and a belt to simplify installation. Partial kits may look cheaper, but they waste time and money in the long run.  A complete kit is the only true way to guarantee pulley alignment and component compatibility. Alternators, for example, may look similar, but have different mounting tab positions. Another example, Concept One presses a hub onto its power steering pumps that in turn accepts a bolt-on power steering pulley. For Chevy LS engines, Concept One Pulley Systems also includes an SFI-rated balancer. 

Lifetime Warranty 

Accessory drive systems include numerous brackets and pulleys as well as drive components and related parts.  Concept One provides a lifetime warranty for all brackets, pulleys, and spacers,  as well as billet power steering reservoirs and billet thermostat housings. With respect to drive components, Concept One supplies parts from well-respected industry leaders, Lares Corporation, Gates, and Continental offer limited lifetime warranties on their respective parts. Powermaster, Fluidampr, Edelbrock, Tuff Stuff, and PRW offer one-year warranties on their respective parts. Gates tensioners are included in all Concept One kits and typically carry an 18-month or 150,000-mile manufacturer's warranty. Check each manufacturer's website for warranty details and conditions.

Brand Name Accessories Included

Many systems on the market supply generic, no-name accessory drive components in their kits.  Concept One pulley systems include brand-name accessory drive components from Powermaster, Fluidampr, Edelbrock, Lares, Gates, Continental, Tuff Stuff, and PRW Power. Concept One has been supplying these brands for many years and can attest to their high quality and performance. 

Mid-Mount Accessory Drive Layout

A proper mid-mount accessory drive system results from compact accessory drive components and careful engineering. Concept One positions all drive components in front of the engine and as close to the engine centerline as possible. The result is improved chassis and header clearance. The mid-mount design also allows for the shortest possible serpentine belt. Avoid systems that mount accessories outboard of the engine using long brackets. Pay particular attention to low-mount accessory drive components such as the power steering pump. You may spend thousands of dollars on a serpentine drive kit only to find that your power steering pump interferes with your frame or steering box.  

Alternator Output and Cooling 

Alternator output and cooling are the most overlooked aspects when shopping for an accessory drive kit. Most systems on the market include older CS130-style alternators.  These alternators feature an external cooling fan that extracts hot air from the front of the alternator and moves it radially. While these alternators work well, many aftermarket pulley kit manufacturers install open "blade" style alternator fans. It's an easy mistake to make, since they look like typical fan blades. While they may look aesthetically pleasing, blade-style alternator fans fail to provide adequate cooling. Concept One Pulley Kits include closed-face alternator fans for any accessory drive kit with CS130 alternators. Most Concept One Pulley Kits have been upgraded to more modern CS130D alternators, which feature internal cooling fans. 

LINKS:

Chevy Pulley Systems

Ford Pulley Systems

Supercharged Pulley Systems