Talk to a Mustang Expert
Mon-Thu 8:30a-11p, Fri-Sun 8:30a-9p

Free Shipping on Everything. Seriously. Details

BBK Underdrive Pulleys (Late 01-04 GT)

29 Reviews
Our Price


  • Item #56008
  • MPN# 1559

  • Market Price $183.99
  • You Save 13% ($24.00)
In Stock Ships same business day. Choose options to add to cart
Free Shipping on Everything
Customer Photos
  • Gain Up to 15HP
  • Three Piece Kit
  • Brilliantly Polished Finish
  • Fits Late 2001 to 2004 GT
Gain 15HP. Improve throttle response and add power throughout your RPM range by reducing the amount of power you're losing to your accessories. And best of all, you don't have to sacrifice your A/C or charging performance - you can free up as much as 15HP with a set of BBK underdrive pulleys for your GT without negatively affecting your Mustang's ability to keep you cool.

Premium Quality. Made of aircraft quality aluminum alloy, these BBK aluminum pulleys won't weigh you down.

Hand Polished. The brilliant polished finish of these underdrive pulleys will give your engine bay a high performance look.

Easy Installation. This BBK Underdrive Pulley kit installs quickly and easily in under 2 hours with no modifications required.

Application. These BBK underdrive pullies are designed to fit the Late 2001 to 2004 GT Mustangs with the short water pump pulley with a bowed in face. Re-uses factory serpentine belt.

Technical Note. Midway through the production run for the 2001 model year Ford changed the design of the water pump on the 4.6L engine. The older style pump produced from 1996 to mid 2001 had a longer shaft. In January of 2001 the design of the pump was changed to a shorter shaft. This necessitated a change in the design of the pump pulley.

Click here to see pictures of the different pulley styles.

Fitment: 2001 2002 2003 2004 Details

What's in the Box
  • (1) Water pump pulley
  • (1) Alternator pulley
  • (1) Crank pulley
Installation Info
Tech Specs
UnderDrive Pulley Specifications
Year/Model: Late 2001-2004 GT Manufacturer: BBK
Material: Aluminum Finish: Polished
Crank Pulley: Piggyback SFI Certified: No
Will it fit my Mustang?
  • GT - 01, 02, 03, 04

Fits Mid 2001 to 2004 GT's Only

Most Helpful Reviews

bbk pullies

Look great i can feel better throttle response

Helpful (1)

Why didn't I do this sooner

Love the pully's!! Cheep in price and noticable power all the way through the RPM band. Only problem is the 3 speeding tickets I got in the last month.

Helpful (22)

Overall Rating 4.7 out of 5 stars
Read All 29 Reviews

Customer Photos (10) Submit Your Photo

View All 10 Photos

You Might Also Like

4 Questions / 2 Answers

Ask a Question

can I put this on my stock 03 mustang gt?


Show 1 more answer Answer This Question I need this answered (0) (0)

will I need to upgrade the alternator for proper charging and upgrade to e to a different fan for cooling? thank John k


Answer This Question I need this answered (0) (0)

Does this require a tune?


Answer This Question I need this answered (0) (0)

More Products You Might Like

Customer Reviews (29) Write a Review

Overall Rating 4.7

out of 5 stars

  • 5/5

    March 08, 2010

    bbk pullies

    Look great i can feel better throttle response

    Matt m

    Helpful (1) (0)

  • 5/5

    June 23, 2010

    Why didn't I do this sooner

    Love the pully's!! Cheep in price and noticable power all the way through the RPM band. Only problem is the 3 speeding tickets I got in the last month.

    J. White

    Helpful (22) (2)

  • 5/5

    July 11, 2010

    BBK UDPs

    Straight forward, easy install, well once you get the stock parts off. Only thing me n my buddy had trouble with was getting the stock harmonic balancer off but once we got it off, the rest was cake. Nice increase in throttle response, my car was noticeably quicker. To the previous reviewer, maybe if you got the right pullies for your year, you wouldn't have had those problems.


    Helpful (18) (3)

  • 5/5

    April 13, 2009

    03 GT

    I added these pulleys and got 12 more horses. Quick and easy hps. Takes 30 minutes tops.


    Year: 2003 Model: GT

    Helpful (9) (0)

  • 4/5

    October 20, 2010

    BBK Underdrive pulleys

    Install was very easy overall. Once I got them on and drove my car i was super impressed at how fast my car picked up when floored. My only gripe is that this is a piggy back setup. If i would have known that I would have bought the Steeda kit instead. Great though if your trying to get the performance and save a few bucks.

    Matt W.

    Driving Style: Daily Driver

    Helpful (8) (0)

  • 5/5

    October 06, 2009

    Worth the price

    Installed on my 01 GT. I put these on after I sold vortech blower and set car up to run nitrous, best thing I ever did, I did a few thousand bucks worth of mods at once so Im not sure if Id notice the power ofem but they look good. O and dont be dumb REUSE UR DAMPER! Just paint it black and bolt it onto the face of the bbk crank pulley like its suppose to be. I see so many people not doing this, Not the smartest thing in my book..


    Year: 2001 Model: GT

    Helpful (6) (0)

  • 4/5

    August 18, 2010

    nice addition

    a fairly simple install, my advice is to get a proper harmonic balancer puller and remove the fan to give you some additional room to work. throttle response was crisper, and no noticeable affect on cooling. great product at a decent price. looks nice under the hood when all polished up


    Helpful (5) (1)

  • 5/5

    Installation Time: Afternoon

    November 11, 2012

    Excellent with a fresh air intake.

    We went on a road trip to Boston. The trip was just over 3800m. I averaged 20.3 mpg. This year we went on a roadtrip to Yellowstone, about 5300m. I averaged 23.04 mpg. The changes in the car between the trips where a fresh air intake, under drive pulleys, and a 3 tune chip. The tune made the least impact in fuel economy. I used the street tune for the trip out on I94 and the stock tune on the I90 heading home. They came back as 24.52 and 24.14 repectively. The flat highway average for the whole trip is 24.35. Not too much difference but it is there. The intake and pulleys took the mileage up over 13%. I think that is pretty impressive. The car is a ragtop. The coupe will do better. On the performance end of things the results are the same. There is a huge difference in driveability. Both the intake and the pulleys changed the way the car performs coming off the line. They made the car feel lighter and stronger. The difference with the chip is there but shows up more on the track performance with the performance 87 and race 91 tunes. The intake and pulleys are must haves, the chip is a nice to have.


    Year: 2004 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 Ottawa, Ontario, Canada

    Helpful (3) (0)

  • 4/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    September 19, 2012

    good product

    It helped my gas mileage a bit and i needed that little extra power to get my stang to 350 hp. AM has never disappointed me and I still purchase products nonstop. Stop reading reviews and just buy it fool!


    Year: 2003 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 2 michigan

    Helpful (3) (0)

  • 5/5

    Installation Time: Afternoon

    September 28, 2013

    great product!

    I ordered these pulleys from AM on a monday and got them on a wednesday. the only hard part of the installation was getting the old pulleys off. Other than that its good to go and I noticed a good gain in tq and hp. I would highly recommend this product to anybody


    Year: 2003 Model: GT Driving Style: Street / Strip

    Helpful (1) (0)

Related Mustang Categories