Mark Houlahan
Brand Manager, Mustang Monthly
June 1, 2003

Horse Sense:
It's not every day that performance aftermarket technology makes its way to the Ford production line. In the case of underdriven performance pulleys, Ford embraced their usage for factory installation on '93, '95, and '00 Cobra R Mustangs.

When it comes to budget upgrades, the first items that often come to mind are underdrive pulleys. Rightfully so, we believe. These little power-making gems have been around for more than a decade. Whether you bolt them to a stone-stock 5.0 or a blown 347, they still make power. With prices less than $200 (some sets are priced less than $100), a pulley upgrade is a nice budget modification that will make power and can usually be used alongside future upgrades with no problems. The one exception would be having to install supercharger crank pulleys in place of underdrive crank pulleys for the installation of a supercharger.

Because most enthusiasts don't factor in labor costs, buying budget performance parts can hit your checkbook with a double whammy when it comes time to install them. Sure, you can get a set of 3.73 gears for less than $200, but it will cost another $200 to have them installed. Underdrive pulleys are similar to throttle bodies, cold-air kits, and performance chips in that the parts are easily installed with simple hand tools. If you have a basic Craftsman tool set, you can install underdrive pulleys.

The typical underdrive pulley kit for 5.0s is a three-piece kit that replaces the crankshaft, the water pump, and the alternator pulleys with either steel or aluminum pieces sized appropriately to slow down these belt-driven accessories. We contacted March Performance to discuss our project, as we wanted a budget-friendly product that would be easy to install and yet be durable and long lasting.

Knowing the pulleys would go on a friend's street 5.0 that is driven every day, we also wanted to have plenty of charging power and coolant flow for stop-and-go traffic. Dan Garn of March Performance suggested the company's tried-and-true best seller-PN 1015. This is a three-piece powdercoated steel pulley set from March's Power & Amp Series, with a 4.375-inch crank pulley, a 5.5-inch water pump pulley, and a 2-inch alternator pulley. Dan guaranteed this set would make power and there'd be no problems in daily driving.

For installation we visited LaMotta Performance in Longwood, Florida, so we could dyno test the effectiveness of the pulley kit. Now grab your tools and let's head to the garage.

On The Dyno
Testing underdrive pulleys might sound trivial, but it's one of those subjects that generates the most questions for us. Do they really make power? Will I have charging problems? As we've said many times before-yes, underdrive pulleys make power. How much? More on a stock car such as the one featured here, but you'll see an improvement even if your car has heads/cam/intake or other such goodies. Take a look and compare the numbers. This 153,000-mile 5.0 picked up solid horsepower and torque all the way from start to finish on the dyno. You can't ask for more than that. Fifteen horsepower for less than 100 bucks-why didn't I think of selling these things!