Product Review – BBK Aluminum Underdrive Pulley Set

Everybody likes cheap horsepower, especially when it’s an easy bolt on. One of the more popular bolt on’s for Mustangs as well as other late model musclecars is the venerable underdrive pulley set.
Underdrive pulleys do exactly what the term implies, they slow down the speed at which the accessories drive. They accomplish this by using different size pulleys on the crank, water pump, and alternator. The alternator and water pump are run at slower speeds while the crank spins more freely. Think of switching gears in your 10 speed bicycle from the big gear in front and the little gear in back to the little gear in front and big gear in back. This slows down the tire and makes it easier for you to turn the pedals. This allows the engine to rev up much more freely and is usually good for 8-10 horsepower.
Unlike engine modifications like cams, cylinder heads and intake and exhaust, underdrive pulleys can be the simplest power freeing modification you can do to your car. Some special tools are required such as an impact wrench to zip off the alternator pulley and a crankshaft dampener puller if your installation requires removal of the crank pulley/dampner assembly but all and all most kits are a simple "Bolted-on" operation.
Installation time takes roughly between thirty minutes and an hour, and even if you’re not a do it your selfer, most shops will charge a minimal price for such an installation. Dollar for dollar it’s one of the best performance upgrades you can make.
The BBK aluminum pulley set consists of some nicely finished pieces that add some good looks to your engine coupled with a large weight loss, thanks to a hand polished finish. These BBK pulley kits are designed as direct bolt on replacements for the current factory pulleys and retain full cooling and charging characteristics. The kit also allows for the use of existing serpentine belts.
The kit I’m installing on my 1983 Mustang 5.0 convertible is the 79-93 3 Piece Aluminum Pulley Kit - 5.0L, part number 1553. This kit is available from American Muscle for $129.99 with free shipping! Here’s the step by step installation.

1. Disconnect your battery. Very important!
2. Loosen alternator nut, water pump and crank pulley bolts while belt is still in tension. (To simplify removal of the alternator pulley loosen with an air impact, with belt in place.
3. Bolts and three factory pulleys can now be easily removed.
4. Install new pulleys with bolts hand tight at this point. Install belt. Torque all bolting per factory specifications. (Use of Loctite thread lock is recommended on all threads.)
5. Check that belt is properly seated in all pulleys. Insure tensioner arrow is within the indicator marks on tensioner. If adjustment is required, relax tensioner from belt, loosen upper 9/16 hex alternator anchor bolt, shift alternator toward air cleaner or allow it to move in as required within the clearance of the diameters. Tighten while holding alternator. If additional adjustment is required, remove belt, loosen ¾” nut while holding tensioner pulley.
6. Set warm idle speed for automatic cars at 650-700 rpm in drive. Standard shift at 750-800 rpm.

And you’re ready to go! Once installed, there is definitely a seat of the pants difference. My 5.0 revs quicker and pulls harder. Definitely an easy and inexpensive way to add some horsepower!