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SR Performance Underdrive Pulleys - Polished (96-Mid 01 GT)

Market Price $96.99 You Save 12% ($12.00)


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  • Item 41129
  • MPN# 41129

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Features, Video & Details

  • Free Up 10-15 Horsepower
  • Complete 3 Piece Kit
  • Durable, Lightweight Aluminum
  • Brilliant Polished Finish
  • Premium Quality Construction
  • Fits 1996-Mid 2001 GT Mustangs

Review & Installation Video

Review & Install Video

Hey I’m Justin with, and I’m going to be breaking down the SR Performance underdrive pulleys, fitting the 4.6L V8 motor found in all 96-04 Mustangs. Engine accessories like the AC compressor, water pump and alternator can really rob your car of horsepower, a great example of how an accessory can really eat up is whenever you turn your car’s AC on, and instantly everything feels a little more sluggish. This is referred to as parasitic drag. The job of an underdrive pulley is to turn the different accessories at a different speed by using a different sized pulley, thus requiring less amount of energy from the engine to turn the accessory belt. This reduction in drag on the crank shaft will allow the engine to work more efficiently, and should equate to more power at the rear wheels. The SR Performance kit does include a brand new crank pulley, a new water pump pulley which will differ depending on your year, a new alternator pulley, and all the hardware and spacers needed for the install. All 3 pulleys have been made from lightweight aluminum and feature a nice bright polished finish, which should definitely help the appearance side of things underneath the hood. As far as the install is concerned, it really shouldn’t be all that bad, ideally, you should have a torque wrench on hand before you get started, as well as some high temp RTV sealant and a breaker bar for that crank pulley. Again this isn’t the hardest job, but you should expect to spend about 2 hours getting everything bolted up. If you should have any problems, you can always reference the detailed instructions along with pictures located on this product page. So if you’re looking to take some of the drag off your accessories, in turn freeing up some horsepower, and improving your throttle response, then you should definitely check out these pulleys from SR Performance, available right here at

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 bright polished finish that will give your engine bay an eye-catching high performance appearance.

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 Polished Aluminum Underdrive Pulley Kit is designed for use on 1996 to 2001 GT Mustangs equipped with the SOHC 4.6L V8 engine and the a long water pump (bowed out 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: 1996 1997 1998 1999 2000 2001 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
    Hardware included:
  • None Required
Installation Info
Tech Specs
Underdrive Pulley Specifications
Year/Model: 96 to Mid 01 GT Manufacturer: SR Performance
Material: Aluminum Finish: Polished
Crank Pulley: Piggyback SFI Certified: No
Will it fit my Mustang?
  • GT - 96, 97, 98, 99, 00, 01

Most Helpful Reviews


I wanted extra horsepower, without spending alot of money, these underdrive pulleys were the exact solution. More h.p. for little $

Helpful (1)

Pulleys installed with my first dyno tune.

It had a significant change with the dyno tune. No heavy lag or draw.

Helpful (1)

Overall Rating 4.4 out of 5 stars
Read All 25 Reviews

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4 Questions / 7 Answers

Ask a Question

what belt size do u use


Show 3 more answers Question Resolved

SR Performance Underdrive Pulleys (96-Mid 01 GT) Does it also give you any torque or just hp?


  • Since torque is the ability to maintain speed against resistance, you will gain torque at your wheels since there is less resistance on the crank pullley.


    Good Answer (2) (0)

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

Does this work on a v6?


  • No, you will need these instead.


    Good Answer (1) (0)

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

99 mustang cobra would this pulleys fit my 99 mustang cobra its a 4.6 dohc


  • If your pulleys look exactly the same as the GT then I would imagine so, just to be sure ask a professional though.


    Good Answer (0) (0)

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Customer Reviews (25) Write a Review

Overall Rating 4.4

out of 5 stars

Installation Time:Afternoon

Installation Cost:$100-$250

  • Performance Gain 4.15 4.2
  • Fit 4.55 4.6

  • 5/5

    August 14, 2016


    I wanted extra horsepower, without spending alot of money, these underdrive pulleys were the exact solution. More h.p. for little $


    Year: 1998 Submodel: GT

    Helpful (1) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    April 25, 2016

    Pulleys installed with my first dyno tune.

    It had a significant change with the dyno tune. No heavy lag or draw.


    Year: 1996 Submodel: GT

    Helpful (1) (0)

  • 3/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    April 21, 2014

    Install was easy some of the bolts don't fit great

    Main bolt for main pulley fits real loose. Had in to put Teflon tape and loctite and lock washer not sure if it will hold. Not a bad price but hassle when everything's coming loose.


    Year: 2001 Submodel: GT Schuylkill Haven, PA, USA

    Helpful (1) (0)

  • 2/5

    April 19, 2011

    not so great....

    Had bad luck from the get go. As bolt did not fit my crank. after finally finding a work bolt, it lasted about 5 months before my crank pulley had cracked! glad i caught it soon! they do look nice, and it seemed to improve throttle response a slight bit, and mid range power seemed a hair better, but not worth the risk. I've read countless horror stories from this set of UD pulley's. GO with Steeda. They seem to have their stuff down!


    Year: 2000 Submodel: GT

    Helpful (9) (3)

  • 5/5

    March 28, 2011

    Underdrive pulleys

    What i liked about this product is the chrome finish thats it has it. They looks great under the hood.The thing i didn't like about the product was that i had to re-use of my old crankshaft pulley to balance it. But for the price it cost i don't mind it because it works great. My car feels like it got a boost in power and thats what i wanted. I would recommend it because is a good product, very affordable an it works great. Than

    Estevan Acosta

    Year: 1998 Submodel: GT

    Helpful (6) (2)

  • 4/5

    Installation Time: Less than 1 Hour

    January 30, 2013

    Easy HP

    Easy to do, and the car runs great. Make sure you get a puller for the crank. Great time to change your belt if needed.


    Year: 1998 Submodel: GT Grayson, ky

    Helpful (2) (0)

  • 5/5

    March 07, 2011




    Year: 1996 Submodel: GT

    Helpful (3) (1)

  • 5/5

    February 26, 2011

    Underdrive pulleys

    Had these installed when I had my alternator replaced. Could tell the difference they made with throttle response off the line. Nice, inexpensive mod.

    Jamis H

    Year: 2000 Submodel: GT

    Helpful (3) (1)

  • 4/5

    Installation Time: Afternoon

    August 18, 2014

    Easier to install than I thought.

    These underdrive pulleys were a little easier to install than I had thought. The instructions could be a little more detailed though. There wasn't enough room in front of the alternator pulley to get my impact wrench in. I ended up removing three nuts that hold the radiator overflow tank on and rotated it clockwise to set it on the power steering fluid reservoir, being careful not to damage/disconnect the hoses. The next issue was trying to remove the crankshaft pulley bolt. The instructions only say to put it in gear for a manual transmission. I had it in 1st gear and it kept trying to turn the wheels. Putting it in 5th gear solved the problem and I was finally able to get the bolt loose. Finally, when I put the new alternator pulley on, the nut would press the pulley against the alternator housing so that it would not turn. The set included a couple bushings but the instructions do not mention them at all. I tried putting one over the alternator shaft but it was too short and did not help. The other one was longer but the inside diameter was just too small to fit over the alternator shaft. Using a hand held rotary tool with a sanding drum I was able to take off enough material to slide it on the alternator shaft. The pulley will then rest on the bushing allowing it to turn once the nut is tightened. The alternator will still put out 14 volts and the cooling system seems to be unaffected by the new water pump pulley. I really don't have a means of measuring performance gain so I rated it as "average."


    Year: 2002 Submodel: GT Jefferson City, MO

    Helpful (1) (0)

  • 4/5

    Installation Time: Afternoon

    August 19, 2013

    Great economy option

    Make sure you have all the tools before you try this, but not too difficult. Looks good under the hood and works like a charm. The alternator pulley is sized perfectly, right on the edge. At idle it produces just enough current to run the ac at max, but turn the lights on or the stereo and it starts pulling a little out of the battery. don't idle all the time with everything cranked you'll be fine. A little gain in hp and mileage. Just slows the serpentine belt down a lot, reduces that parasitic drag. Definitely a good investment. If the battery light comes on after install, check the alternator fuze. Mine was blown.


    Year: 1997 Submodel: GT Libby Montana

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    April 11, 2013

    Really helped free the engine up

    The SR pulleys really help free up horsepower that the engine had all along! and they look great! Overall very happy with the purchase. Thanks American Muscle!


    Year: 1997 Submodel: GT TX

    Helpful (1) (1)

  • 5/5

    Installation Time: Less than 1 Hour

    December 09, 2011

    alot better on gas

    this kit makes your uder hood look better and better on gas n i feel a more power out of it. i would recommen this to ever one...


    Year: 1998 Submodel: GT texas

    Helpful (2) (2)

  • 5/5

    Installation Time: Less than 1 Hour

    January 26, 2012

    Great, just great!!

    Good product, only thing I have to say is make sure you got some additive for your coolant in the summer or else if you got a lot of miles, the engine WILL run extra hot because of the enlarged water pump pulley tugging on the output of the water pump. It can be a nuisance when your engine starts to bog down due to A/C and heat again... Overall though I like the performance!


    Year: 2001 Submodel: GT St. Louis, MO

    Helpful (0) (1)

  • 5/5

    Installation Time: Afternoon

    May 16, 2012


    This product is amazing , this was the second thing I bought from AM, its a pretty good price for something that's gets ur pony reving higher when you want it to , I took mine to a local shop n it didn't charge much like 50-80 bucks, but its looks good under the hood as well with the Chrome finishes, I bought this with a cai n raced a 97 cobra in the freeway, and I keep blowing him out the water, I don't recommend you to race in the freeway but still lol atleast u get the point, this product


    Year: 1998 Submodel: GT Detroit, MI, USA

    Helpful (3) (8)

  • 4/5

    Installation Time: Full Day

    July 04, 2016

    Good bang for buck

    Nice product and they look sweet install went well until the crank shaft pulley, bolts that it comes with are to small so I had to go buy new ones


    Year: 1999 Submodel: GT

    Helpful (0) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    June 29, 2016

    Great item

    Fits according specification from a vendor, is on a pretty shape at the moment to receive..


    Year: 2000 Submodel: GT

    Helpful (0) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    June 12, 2016

    Great product

    The kit is a great product fast and simple install as long as you have the right tools, notice better throttle response.


    Year: 2001 Submodel: Bullitt

    Helpful (0) (0)

  • 5/5

    May 22, 2016

    SR Performance Underdrive Pulleys

    I have not installed it but the quality is great. Can't wait to see the results.


    Year: 2000 Submodel: GT

    Helpful (0) (0)

  • 4/5

    Installation Time: Afternoon

    August 26, 2014


    Great product, easy to install with the right tools. Very satified


    Year: 1996 Submodel: GT Cowansville, QC, Canada

    Helpful (0) (0)

  • 5/5

    Installation Time: Afternoon

    March 15, 2014


    These pulleys are good on your wallet and you can definitely feel a difference in your throttle.


    Year: 2001 Submodel: GT

    Helpful (0) (0)

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