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Ford 10-Rib Serpentine Belt; 84-7/8-Inch (07-14 Mustang GT500)

Item 101399
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      Video Review & Installation

      Justin: Hey, Justin with here with a stage three, power pack bolt-on build up for an all '07, '09 GT500's. The focus of the stage three power pack is to take our already worked up GT500 to the next level and beyond. How are we going to get there? Well, for one, we're going to make sure our cars ready to flow some serious air, improving on both the intake and exhaust side of the equation. On top of that, we're going to add a little bit more boost to our car and see what kind of numbers are possible with the factory Eaton m122 blower still in place. For starters, lets set the table for a little bit more boost. Once you start getting around 550 wheel horsepower in these cars, that factory throttle body really becomes a big restriction. And since we're pretty much already there now with our basic bolt-ons and 2.6" pulley, that factory throttle bottle just had to go. In its place now, is the Ford Racing twin 65 millimeter cobra jet throttle body. This is the same throttle body used on the purpose built, Cobra Jet drag car so you know its proven. This is going to replace the twin 60 millimeter stoker with twin 65 millimeter openings, allowing much more air into the super charger and into the engine. Since it is a Ford Racing part, you know the quality, the fitment, and the electronics are all going to be dead on. And lastly, I know we're all about performance here in these power packs, but you can't deny, this is a very good looking part. Polished billet construction and the Ford Racing logo looks so good under the hood, especially along side that JLT carbon fiber intake. Now that we open up things on the intake here, lets take a closer look at the exhaust. One of the biggest disruptor in exhaust flow on any car is the factory cats. They're just performance killers, and that was certainly the case here with our Shelby's. So to fix that, we installed this off road x pipe here, full stainless steel construction throughout, mandrel bends, and 2 3/4 inch tubing. Best of all, really going to uncork the flow of exhaust and should transform our exhaust note into something much more sinister. Speaking of that exhaust note, if getting rid of the factory cats weren't enough, add flow masters outlaw series axle back here has definitely given this thing, a tone worth of one of the baddest Mustang's of all time. In fact, listen for yourself. We chose the outlaw series again because of its straight through design which is going to increase the flow of exhaust, when working with that off road x pipe we just mentioned. Now this is basically just to ensure that our GT500 is ready to move some serious air, which is very important here in the stage 3 power pack because we are going to be throwing a few extra pounds of boost at our car. So with that said, lets get out from underneath the car, head back up to the engine bay, and I'll show you guys where that extra boost is going to be coming from. Since we already have the 2.6" upper pulley here in our GT500, the options for adding more boost are a little limited. In fact, the easiest and really only way to do so, is by adding a larger, lower balancer. So we installed a ten percent lower balancer from Innovater's West here on our '08 GT500. The 2.6" pulley with that balancer is actually a very popular choice with any GT500 owners looking to get the most out of those Eaton blowers. The Innovater's balancer is much lighter than our factory '08 balancer, which will be dropping a rotational mass and by increasing the diameter by ten percent we should be looking at three to four pounds more boost, which will put our Shelby at about fifteen or so pounds of boost when its all said and done. This is pretty much the safe, tried and true limit of efficiency of these factory and 122 blowers, that is of course, without any additional cording or pulling, like meth injection. You start spinning them any faster and heat really becomes an issue, and at that point the super charger begins to loose its efficiency, which means a drop in power. To help keep things cool here in our Shelby, we installed the Afco Pro Series heat exchanger which does include dual ten inch electric fans, to help keep things even cooler. The Afco itself is a very nice piece. Its built extremely well, its great, and it does include everything you need for a painless instal. Because of this, its an extremely popular choice with terminator owners and their GT500 owners out there. In fact if you want to read up on some of the reviews, or learn more about the heating danger itself, just go ahead and click on the link below to visit the product page. So now that we have all of our stage three mods in place, we're gonna move the car over to the Dino and let Mike in the band of performance team step in and let them do their thing, but before we do, I just want to remind you guys to subscribe for our YouTube channel if you haven't done so already, just to check out some of our other bolt-on build ups and more mustang content. All you have to do is simply click on that link below.When the stage two power pack was all finished up, the car was making 548 horsepower, and 545 pound feet of torque. A the end of the stage three power pack, the car is now making 581 horsepower and 600 pound feet of torque. Giving us a peak gain of 33 horsepower over our stage two numbers, and gains of 47 horsepower, and 59 pound feet of torque throughout the curve. So to recap, with all three power packs installed, we went from a base line number of 434 horsepower and 432 pound feet of torque at the rear wheels. 581 horsepower and 600 pound feet of torque. That gives us a peak overall gain of 147 horsepower and gains of 157 horsepower and 169 pound feet of torque throughout the curve. That's going to do it for the stage three power pack bolt-on build up for the 2007 to 2009 GT500. Our 2008 GT500 started out as a pretty formidable street car, but over the course of three different power packs which included a bit more boost, bolt-ons, and a quality tune, it has turned into an absolute monster that is ready for just about any challenger that might want to test it. At the track, or at the next red light, we hope you guys have enjoyed watching these power packs, don't forget to check out stage one and two, and for all things Mustang, keep it right here at

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • Genuine OE Ford Part Number 7R3Z-8620-A
      • Required for 10% Overdrive Harmonic Balancer Pulley Install
      • 10 Ribbed V Belt
      • Circumference: 84-7/8"
      • Genuine Ford Part: JK10-847
      • Fits 2007-2014 Shelby GT500 with 10% Overdrive Harmonic Balancer


      Required for Installation. If your planning on running the Innovators West 10% Overdrive Harmonic Balancer Pulley on your 2007 to 2014 Shelby GT500 for more power, you are going to need this larger serpentine belt to keep tight on your blower for maximum boost.

      Routine Maintenance. Keeping your Shelby GT500 running strong means routine maintenance, which includes replacing your old, cracked and slipping serpentine belt with a brand new replacement Serpentine Belt from AmericanMuscle.

      Application. This Ford Serpentine Belt is designed to fit 2007 to 2014 Shelby GT500's equipped with either the 5.4L or 5.8L supercharged engine that are upgrading to the Innovators West Overdrive Harmonic Balancer Pulley.

      Technical Note. It is recommended to replace your belts at intervals of approximately 3 years or 36,000 miles.



      Ford 7R3Z-8620-A

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Serpentine Belt

      Tech Specs


      Customer Reviews (7)

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        Reviews of Ford Engine products have an average rating of 4.8 out of 5

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          Will It Fit My Mustang

          • GT500 - 07, 08, 09, 10, 11, 12, 13, 14

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