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BBK Underdrive Pulleys (05-10 GT)

Market Price $305.09 You Save 12% ($35.10)
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  • Item 56030

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    Features & Details

    • Gain Up to 12HP
    • Brilliantly Polished Finish
    • Easy Installation
    • SFI Certified
    • Fits 2005-2010 4.6L Mustangs
    Gain 12HP. You may not know it, but your accessories are robbing your Mustang of nearly 12 horsepower. Get that horsepower back with a set of SFI approved underdrive pulleys from BBK. BBK's Underdrive Pulleys reduce the drain your accessories place on your engine, freeing up more horsepower and improving throttle response, without affecting your Pony's charging or cooling characteristics.

    Premium Quality. The BBK SFI-approved underdrive pulley set for your S197 4.6L is CNC machined from aluminum and steel components to ensure it will perform to the highest standards. With a brilliantly polished finish, this piece also looks great underhood.

    Easy Installation. The BBK SFI-approved underdrive pulley kit comes with complete instructions for an easy install and requires no other modifications.

    SFI Certified. By choosing an SFI Certified product, you're ensuring the product you choose has been made to the highest standards for quality and safety.

    Application. These BBK Underdrive Pulleys are specifically designed for use on the 2005 to 2010 Mustangs powered by the 4.6L V8 engine.

    Fitment: 2005 2006 2007 2008 2009 2010 Details

    MPN# 1653

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (1) Crank Pulley
    • (1) Alternator Pulley
    Installation Info
    Tech Specs
    UnderDrive Pulley Specifications
    Year/Model: 2005-2010 GT Manufacturer: BBK
    Material: Steel Crank/ Alum Access. Finish: Polished
    Crank Pulley: One Piece Crank SFI Certified: Yes
    Will it fit my Mustang?

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    Questions & Answers (9)

    5 Top Rated Questions

    Do you have to have a tune when changing out the pulley?

    • The BBK Underdrive Pulleys for the 05-10 GT Mustangs will not require a tune.

    Helpful (1)

    Do I use the same belt ? Form stock or I need to change with this pulley?

    • The factory belt will work with the BBK Underdrive Pulleys.

    Helpful (0)

    Will this work with a 5.4 f150 2005?

    • We are unable to confirm fitment with any vehicle other than the 05-10 Mustang GT's.

    Helpful (0)

    hi i a have supercharger edelbrock stage 2 in my mustang gt 4.6 2006 and he put underdrive pulley my question is so good or no good

    • These underdrive pulleys would work even if you have an aftermarket supercharger on your Mustang.

    Helpful (0)

    What takes up the slack on the belt from a smaller pully.Would it be the water pump pully is larger?

    • The slack is picked up by the tensioner. As long as your tensioner is good and tight it will take up the slack.

    Helpful (0)
    Post Your Question
    4 More Questions
    My mechanic use installation Bolt claiming that the original Bolt was too short to install it will it cause any problems to my car 1 answer
    Will this affect the performance of the A/C? 1 answer
    Are these compatable with the Roush m90 supercharger for a 2006 gt? 1 answer
    Bolt specs, i lost mine, need a replacement so i ordered my underdrive pulleys, havent put them on for several months, then i come to find out my bolt that came with, is missing, does Anyone know the specs about that bolt. I.E. size, thread count, and length. thank you so much!! 1 answer

    Recommended For You

    Customer Reviews (24) Write a Review

    Overall Rating 4.5

    out of 5 stars

    Installation Time:Afternoon

    Installation Cost:$100-$250

    • Performance Gain 4.066667 4.1
    • Fit 4.2 4.2

    • 5/5

      Installation Time: Afternoon

      December 09, 2018

      nice upgrade

      easy to install if you follow the instruction submitted by a customer.look much better than the factory ones.would purchase again and recommend to anyone


      Year: 2006 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      September 17, 2018

      BBK underdrive pulleys

      Easy to install, damper bolt could make or break the deal. Be prepared to get a tightly torqued bolt loose. I put car in 3rd gear with parking brakes on, still wasn't easy


      Year: 2005 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      July 23, 2018


      Had VT Performance in Oceanside install while installing BBK throttle body and CAI. Everything looks great. It’s a completely different car. Would recommend these bolt ones to anyone looking to go faster yet still remain smog legal.


      Year: 2005 Submodel: GT

      Helpful (6)

    • 5/5

      Installation Time: Less than 1 Hour

      March 04, 2018

      Easy install

      Worth the money. Quicer rev. Easy install and good add on


      Year: 2005 Submodel: GT

      Helpful (6)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      September 30, 2017

      BBK Underdrive pulley

      I felt good about my purchase,there were a little complication with the new bolt but with that resolved.I notice there is some difference in performance.


      Year: 2008 Submodel: GT

      Helpful (8)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: 0-$100

      September 07, 2017

      BBK pulleys are great!

      I have just completed having BBK Underdrive Pulleys installed on a 2010 Mustang GT that I recently acquired. The 2010 GT has an automatic transmission, so I will soon be testing out the performance. I expect good results because I already have the same BBK pulleys installed on my older 2007 GT with a 5-speed manual tranny. I have been pleased with performance on my 2007. The BBK pulleys fit well and look Great!


      Year: 2010 Submodel: GT

      Helpful (6)

    • 5/5

      Installation Time: Afternoon

      December 01, 2013

      Looks Nice

      This is the second one I have installed and went on as expected. I bought a puller at Harbor Freight and so far it has installed two set without issues. Just buy a new crank bolt to replace the original and the install should go without any hitches.


      Year: 2008 Submodel: GT Paducah, KY

      Helpful (7)

    • 4/5

      Installation Time: Afternoon

      May 24, 2013

      Great Product, just a couple catches

      These pulleys look great and they provide a noticeable gain to power and throttle response and *maybe* a 1mpg gain. Just know that a couple of 'gotchas' come with installing these. First off, I had to cut down one of the bolts on the pump because the water pump pulley was making contact, which is obviously not good. The second problem is that it is very hard on alternators. Since installing these in mid 2011 I've gone through 2 alternators because the pulley is running at a different speed and chewing them up. My next alternator is going to be more solid so hopefully it will hold up, but if you aren't willing to buy anything better than autostore brand refurbished alternators then this product is not for you.


      Year: 2006 Submodel: GT

      Helpful (8)

    • 5/5

      Installation Time: Afternoon

      January 27, 2013

      Great product

      Easier to install then I expected. Looks great, more power and better gas mileage. Really a great product.


      Year: 2010 Submodel: GT Orlando, Florida

      Helpful (8)

    • 1/5

      Installation Time: Afternoon

      June 18, 2012

      More Power, Less Handling

      I had this pulley installed by a shop. They said the bolt it came with was not the right thread type for my car and that the bolt was a low grade. So they had to use the factory bolt. When I got it back the first thing I noticed was the HP gains at the top end. Though after a couple of long drives I noticed the negative effects, on long hills there’s definitely a noticeable loss in low end torque but the big one is the steering on bumpy roads the front end becomes unstable and on smooth roads the car seems to understeer more. The reason is the pulley kit is designed to slow down the rotation of engine accessories one of which is the power steering pump. The low rotation causes a lower pressure in the system which is very noticeable at higher speeds. And to let you now the suspension on my car is not stock. I have steeda adjustable anti-roll bars, a strut bar, and rear adjustable control arms. So the steering effects are more noticeable than stock.


      Year: 2008 Submodel: GT Flagstaff, AZ

      Helpful (8)

      • Response from AmericanMuscle

        We've forwarded your feedback on the included bolt to BBK. Our purchasing team will work with them to make sure they're including the right bolts (and high quality bolts) with these kits. As you said, underdrive pulleys are designed to cut power to all of your engine accessories, leaving more power to your engine itself. We don't often hear of customers noticing any negative handling effects from any underdrive pulley kit.

        Rob Hunt, Customer Care

    • 5/5

      Installation Time: Afternoon

      June 01, 2012

      good product

      good product, it would have been nice to get the alternator bolt that comes with other products from other sites but i'm loyal to AM. if you can't break the bolt loose just use the "crank method". make sure you take the fan and air box out, position a breaker bar up against the passenger wall of you engine bay and make sure it is connected to the crank bolt, and crank over your engine..don't start it..just break the nut loose. after that it was just like the instructions as far as install. i had to grind the alternator bolt down for the water pump pulley to have clearance.


      Year: 2007 Submodel: GT California, USA

      Helpful (8)

    • 1/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      May 20, 2012

      Poor quality/ dont waste your money!

      I bought these underdrive pulleys based on these "ease" of installation, the BBK name and for performance. The instructions were clear but as we did everything the way instructed, the longer bolt given for installation stripped. I took it to a Ford dealer where the Mustang tech had to finish the install. He said the instructions with the longer bolt is the wrong way to do it and finished the install for me. He said the crank pulley was flush against the seat. They have squealed ever since. I have tried numerous things to resolve the problem with no success. There was no noticable power increase. They look good but I am going to have to pay to put the factory pulleys back on. I dont recommend this mod. Spend your money elsewhere on a better mod. Oh by the way, BBK wont return emails or phone calls to help either! American Muscle is great and I will continute to buy from them. These pulleys just suck.


      Year: 2007 Submodel: GT Huntington, WV, USA

      Helpful (9)

    • 5/5

      Installation Time: Less than 1 Hour

      April 03, 2012

      Awesome Product

      I really don't feel a difference in my accessories; however, decent gain in hp. I installed with FR500 Axlebacks & Magnaflow True-x w/ High Flow Cats.


      Year: 2007 Submodel: GT Danville, VA

      Helpful (7)

    • 5/5

      Installation Time: Afternoon

      March 19, 2012

      2010 GT Convertable

      This was an easy install. Didn't even have to remove the fan, there was enough room to use a 4 inch puller.


      Year: 2010 Submodel: GT Fort Irwin, CA

      Helpful (9)

    • 5/5

      Installation Time: Less than 1 Hour

      December 27, 2011

      Nice gain / lillte costs

      Not a bad gain for little costs. Free up some HP !!


      Year: 2007 Submodel: GT

      Helpful (7)

    • 5/5

      May 24, 2011

      Great Product

      Great product looks fantastic in my engine bay. When you go to a parts store to rent the pulley puller, make sure you get the chrysler one with the three prongs, just like the instructions say. My crank pulley was badly rusted so it took about 30 tries to get that thig off, but it was worth it (my mechanical skill is low, so I blame that) I also had a clearance issue with a bolt on the alternator rubbing on the water pump pulley, so I ended up trimming the bolt. Engine revs faster, and I have been getting 30 miles/tank better, which will pay for the part eventually (which is what I told my wife). Great part from AM, I don't buy my parts anywhere else


      Year: 2006 Submodel: GT

      Helpful (11)

    • 5/5

      April 27, 2011

      Gret product

      Great product adds good response to your car. Install instructions are thorough and helpful. Great bolt on for your car.

      Michael S

      Year: 2006 Submodel: GT

      Helpful (7)

    • 5/5

      November 20, 2010

      good so far

      looks great, pull the fan (super easy) and have impact wrench. get a new crank bolt from ford for they are torque turn. 1 time use application. have an impact wrench and a torque wrench. the final install torque (36 ft lbs +90 degree turn) seemed to be a 1/2 inch impact as tight as it goes. make sure you silicone the key way. a 3in 3 jaw puller worked great, i put the socket on the bolt and used that to keep the puller shaft centered. havent thrashed on it yet cuz i had a trunk full of tool box and didnt want it smashing up my trunk and i wanted to let the silicone dry


      Helpful (17)

    • 5/5

      October 21, 2010




      Helpful (12)

    • 5/5

      October 15, 2010

      BBK SFI Underdrive Pulley System

      I was looking for easy ways to improve my Mustang's horsepower and the BBK pulley system sounded just right. The pulley system couldn't be any easier to install.Took me about an hour to do the job. BBK provides the instructions straight to the point. I noticed that with this pulley system I freed up some horsepower by eliminating the power robbing drag that the original harmonic balancer would cause. I like the product, its great, it improved my throttle response and gave me a little more gas mileage. The pulley system doesn't affect your cooling system nor your charging system but, one thing (minimal) I disliked was for the air conditioning to delay a little beacause the pulley system does cause a slow down on your belt accessories (which is good) with out compromise but the a/c compressor needs a little more speed on the belt to let it engage it's clutch. Overall the product is great and it definitely gives a better look under the hood with the aluminum water pump pulley and the billet harmonic balancer. Once you have it, you won't regret have boughten it.

      Esteban Ramirez

      Helpful (9)

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