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SR Performance Underdrive Pulleys - Black (Late 01-04 GT)

Market Price $169.99 You Save 18% ($30.00)
Our Price

$139.99

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  • Item 525575
  • MPN# 525575

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Features, Video & Details

  • Free Up 10-15 Horsepower
  • Complete 3 Piece Kit
  • Durable, Lightweight Aluminum
  • Black Powder Coated Finish
  • Premium Quality Construction
  • Fits Late 2001-2004 GT Mustangs

Review & Installation Video

Review & Install Video

Free Up Horsepower. A set of SR Performance Underdrive Pulleys reduce parasitic drivetrain loss by cutting down the amount of power your accessories take up, these underdrive pulleys will free up 10-15 horsepower, without sacrificing cooling and charging functionality of your Pony.

Premium Quality Construction. CNC-machined from lightweight aircraft grade quality aluminum alloy for strength and durability, these SR Performance pulleys feature a gloss black powder coated finish for aggressive good looks and long lasting corrosion resistance.

Easy Installation. These SR Performance Mustang Underdrive Pulleys installs quickly and easily in under 2 hours with no modifications required.

Application. This SR Performance 3-Piece Aluminum Underdrive Pulley Kit is designed for use on Late 2001 to 2004 GT Mustangs equipped with the SOHC 4.6L V8 engine and the a short water pump (bowed in face). Reuses factory 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) Crank Pully
  • (1) Water Pump Pully
  • (1) Alternator Pully
  • (4) Bolts
  • (3) Washers
  • (2) Spacers
  • (1) Instruction Sheet
Installation Info
Tech Specs
Underdrive Pulley Specifications
Year/Model: Late 2001 to 2004 GT Manufacturer: SR Performance
Material: Aluminum Finish: Black Powder Coat
Crank Pulley: Piggyback SFI Certified: No
Will it fit my Mustang?
  • GT - 01, 02, 03, 04

Fits GT Mustangs with the short water pump with a bowed in pulley.

People Who Bought This Item Also Bought

Most Helpful Reviews

5/5
Great Starter Mod

Great product overall. Everything fit fairly well. The instructions are easy to follow and also gives tips to help with the install. The pulleys look great. No chips or scratches in the paint. Having all ...

Read More
Helpful (1)

5/5
Sr performance

You can feel the difference my car has more ponies. Thank AM for another great product

Helpful (1)

Overall Rating 4.9 out of 5 stars
Read All 21 Reviews

Customer Photos (1) Submit Your Photo

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3 Questions / 4 Answers

Ask a Question

would this fit 3.8l mustang 99

Joosebox

  • These SR Performance Underdrive Pulleys would not fit your 3.8L, 1999 Mustang, I apoligize. We unfortunately do not currently carry a pulley kit for your year-model Mustang.

    AMJEFF

Show 1 more answer Helpful (0)

What size belt is needed?

Scrotus

  • These underdrive pulleys are able to reuse the stock belt. You do not need to buy a different size.

    AshleyK

Helpful (0)

Does Item# 525575 fit an 04 4.6L Crown Vic Police Inter. motor?

2002slow2V

  • While there are many similarities, we unfortunately are not able to confirm fitment on your vehicle, I apologize.

    AMJEFF

Helpful (0)

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Customer Reviews (21) Write a Review

Overall Rating 4.9

out of 5 stars

Installation Time:Afternoon

Installation Cost:$100-$250

  • Performance Gain 4.25 4.3
  • Fit 4.75 4.8



  • 5/5

    August 05, 2016

    Great Starter Mod

    Great product overall. Everything fit fairly well. The instructions are easy to follow and also gives tips to help with the install. The pulleys look great. No chips or scratches in the paint. Having all the tools in the tool list will make the install go faster. I used a strap wrench to help with the crank pulley. I can feel a difference when I drive. It was not a huge difference, but definitely enough to put a smile on my face.

    StreetMuscle

    Year: 2003 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    June 03, 2016

    Sr performance

    You can feel the difference my car has more ponies. Thank AM for another great product

    Truly03Gt

    Year: 2003 Submodel: GT

    Helpful (1)

  • 4/5

    Installation Time: Afternoon

    March 10, 2016

    More power, not bad.

    Great little mod, hate that I had to use the old harmonic balancer and piggy back it with this. But, for how big of a pain in the butt it was to do this, it was worth it. 1. Unscrew the 3 bolts for the coolant reservoir and move it for some room 2. Use impact fun on alternator and loosen the bolt and take it off with impact. Won't work any other way that I could find. 3. Loosen water pump pulley bolts. 4. Breaker bar, car in 5th gear. Crack loose the crank pulley bolt. Take belt off 5. Use pulley puller to get harmonic balancer off 6. use the 3 bolts with the 3 washers to squeeze the harmonic balancer and the new pulley for the crank together. @ 12 lb trq 7. Use the bigger ring supplied from package for alternator pulley and swap them out with the new ring behind the alternator pulley 8. Water pump pulley self explanatory 9. Put harmonic balancer with new pulley facing motor and fit into key way, get in far enough to start using the supplied bolt to install. When put in all the way crank to 60 lb trq. 10. Put belt on

    MooStang

    Year: 2004 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    February 18, 2016

    SR underdrive pulleys

    Good quality, easy to install, good Hp gains. Great starting mod!

    Cole

    Year: 2002 Submodel: GT Joliet, IL

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    December 20, 2015

    UpGrade

    Great upgrades , you can feel the increase in horse power. I will be adding tuner next , then headers.

    timmy

    Year: 2004 Submodel: GT eden , nc

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    December 11, 2015

    Easy Install and BIG Performance Upgrade!!!

    These are a must buy!!! Easy 1 hour install on my 03 auto GT and picked up 10 HP! You won't regret, it buy it now! Thanks AM!

    Nate

    Year: 2003 Submodel: GT St. Louis, MO

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    December 10, 2015

    WOW!

    As a Canadian customer, I received my parts in about a week. It was well packaged to prevent damages. The instructions were easy to understand and the job was done quickly. Excellent pricing and parts quality.

    Steph572

    Year: 2002 Submodel: GT Québec city, Canada

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    December 10, 2015

    Sr under drive pulleys

    Really love it !!! I can feel the gain ...really recommend it

    REAPER

    Year: 2003

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    December 10, 2015

    Easy n simple

    Easy step by step instruction s just need to get a harmonic balancer puller and a breaker bar and job will be a piece of cake

    Mikev

    Year: 2002 Submodel: GT Los angeles

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    November 13, 2015

    Simple Install

    These underdrive pulleys are super easy to install and fit great. Simply remove the electric fan to gain a few more inches of work space and the rest is a breeze. All the parts and hardware included fit right with zero modifications. My mustang now has more low end pull. Would def recommend this kit.

    NapaMike22

    Year: 2003 Submodel: GT Woodstock, CT

    Helpful (1)

  • 4/5

    Installation Time: Afternoon

    October 22, 2015

    Don't buy painted

    Don't buy painted they paint were your seal rides! I just don't trust that. Other than that it was easy not a huge power gain lil bit by couldn't feel to much but every little thing counts in the end

    Builditfasteritstoslow

    Year: 2002 Submodel: GT Petaluma ca

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    August 27, 2015

    Definitely a performance upgrade

    Can really tell the difference when u throw these pulleys on.. More low end torque and perfect fit.. Def should be one of ur first upgrades to ur stang..

    04roushman

    Year: 2004 Submodel: Other Hollister, CA, USA

    Helpful (1)

  • 5/5

    Installation Time: Less than 1 Hour

    March 23, 2015

    SR PERFORMANCE PULLEYS

    Great Product, very easy to install. This underdrive pulley kit works well with my other mods, the motor spins up a little faster. Highly recommended for the price!

    KOZ16

    Year: 2003 Submodel: GT Macomb, MI

    Helpful (1)

  • 5/5

    August 07, 2017

    Underdrive pullies 03 mustang

    Nice black finish, fit perfectly. Easy to install.

    RogerH

    Year: 2003 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    Installation Cost: $100-$250

    July 14, 2017

    Sr performance underdrive

    Awesome kit , easy to install in glad I choose this kit !! No complaints

    CammiM

    Year: 2001 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    July 12, 2017

    Great buy!

    Easy to install. Marginal difference but important for the overall build.

    ChaseT

    Year: 2003 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    June 07, 2017

    GOOD BUY!

    I PUT THESE ON AND NOTICED A DIFFERENCE IN ACCELERATION.

    04gtHELLRAZOR

    Year: 2004 Submodel: GT

    Helpful (0)

  • 4/5

    Installation Time: Less than 1 Hour

    May 29, 2017

    Battery ran dry

    I love the boost in low end torque, but it seems that you need to upgrade to a higher output alternator. My car ran the battery dry and I had to get towed back home. The description says no change in cooling or charging but I found that to be untrue. Wish they would have said something, otherwise 5/5.

    JeffS

    Year: 2002 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    April 17, 2017

    Lighter than spected

    Fits perfect. Kit includes everything needed apart from the puller

    Kenner

    Year: 2003 Submodel: GT

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    March 17, 2017

    Underdrive Pulleys

    Great product. Easy quick install tool about 30minutes given that I had to let the car cool down. Hardware that comes in the box is handy and the black finish on the pulleys cleans up the look.

    JesseZ

    Year: 2002 Submodel: GT

    Helpful (0)

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