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Comp Cams Mutha Thumpr Cams (05-10 GT)

Market Price $806.99 You Save 12% ($94.02)
Our Price

$712.97 (pair)

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  • Item 30138
  • MPN# 127020

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Features, Video & Details

  • Very Rough Muscle Car Idle
  • Biggest Cam Available for Stock Heads
  • Great Power Above 4900 Rpm
  • No Springs Required ("NSR") - Compatible W/Stock Valve Springs
  • Fits 2005-2010 4.6L GT and Bullitt

Review & Installation Video

Review & Install Video

Hey, Justin with here, taking a closer look at the Comp Cams Mutha Thumpr Camshafts available for the 3-valve motor found in all 2005 to 2010 Mustang GTs. A set of new cams for your 4.6L is just one of many different ways to pull more power out of your 3-valve motor. Now if you're looking for more ways to increase the horsepower and torque in your Mustang, go ahead and click on the link below to subscribe to our YouTube channel or you can check out many of our different builds, including one very nasty 3-valve named Project Grabber Boost. Comp is one of those names that just about every Mustang fan should be familiar with. They've been producing quality camshafts and valve train components for over 35 years, making them one of the best in the biz. The Thumpr series camshafts are just one of many different cams offered by Comp and will give your GT a serious hot rod idle thanks to long exhaust duration along with some nice performance gains without having to replace your stock valve springs or retainers. In fact, Comp says that the Mutha Thumpr here is the largest cam they offer for the stock heads that will give you some nice performance gains throughout the entire power band but they really shine above 4900 RPM. In fact, go ahead and click on that link below to check out some of the customer reviews about these camshafts. While you're there, you can actually check out a video that one of our customer's link to his own ride, which will give you a good sense of how your idle will be with these cams in your 4.6. I do want to point out that, in addition to the cams themselves, you will need to pick up Comp's Cam Phaser Limiter kit, which is available from a drop down tab located on the product page. This allows your motor to still retain the use of its variable valve timing but will limit the total cam timing to prevent any piston to valve contact since the 3-valve is an interference motor. In addition to the Cam Phaser Limiter kit, of course you will need it custom-tuned, which is available from the bandwidth performance team. Installing a new set of cams along with the limiter kit is a job that should ultimately be left up to your local mechanic or speed shop due to the complexity of the work. On the other hand, if you're the type of person that likes to tackle any and everything with your ride, then go ahead and leave yourself about a full-day in the garage to get the job done. If you should have any questions about the install or about the Comp cams in general, you guys should know what to do by now. Hit us up with our 800 number or feel free to write us an email. If you've been looking to cam your three-valve and you wanna run the biggest possible cam with the stock heads, valve spring or retainers still in place, look no further than Comp Cams Mutha Thumpr Camshafts available right here at

Mutha Thumpr. Comp Cams Mutha Thumpr Camshafts really live up to their name. These are the largest aftermarket camshafts you can run with the stock heads. These Comp Cams produce great power gains over 4900 RPM's with a very rough muscle car idle.

No Springs Required. These cams are compatible with your stock valve springs, so there's no need to remove and replace your 24 stock springs, saving you time and money.

Application. Comp Cams Mutha Thumpr Camshafts are sold as a pair for your 2005 to 2010 3V 4.6L modular powered Mustang, including both the GT and Bullitt models.

Technical Note. The installation of these Comp Cams will require a phaser limiter kit and custom ECU programming.

Fitment: 2005 2006 2007 2008 2009 2010 Details

What's in the Box
  • (2) Camshafts
Installation Info
Tech Specs
Comp Cam Data Sheet
Part Number: 127020 Grind Number: MT273LL
RPM Range: 750 to 6600 Engine Type: FORD 4.6 and 5.4 SOHC MODULAR 3-V
Lobe Sep Angle: 109

Intake Exhaust
Duration: 273 306
Duration @ .050" Lift: 234 254
Valve Lift: 0.45 0.45
Will it fit my Mustang?
  • Bullitt - 08, 09
  • GT - 05, 06, 07, 08, 09, 10

Fits 2005-2010 4.6L Three Valve Mustangs Only

People Who Bought This Item Also Bought

Most Helpful Reviews

these cams are the way to go!

I had these cams installed and absolutely love them, particularly when I pull in and leave car shows. Everybody is looking around to see where the camming hot rod is coming from and realize it is a newer ...

Read More
Helpful (16)

Monster Sound!!!!!

My local speed shop suggested these cams to me when I was serious about upgrading. At first I was a little disappointed when I realized I would have to buy the additional component (Phaser Limiter Kit) ...

Read More
Helpful (15)

Overall Rating 4.9 out of 5 stars
Read All 36 Reviews

Customer Photos (6) Submit Your Photo

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37 Questions / 12 Answers

Ask a Question

How much horespower gain will i notice with this?


  • I have these cams put on with a full exhaust, in order to get the real feel of these cams you need to have long tube headers, an X pipe or H pipe of some sort as well as axlebacks. It's a huge difference compared to the stock cams, so you'll be looking at real horse power gains with supporting mods of about 30 RWHP, which is alot more than you think it is!


Show 2 more answers Helpful (6)

Can these be put in an 06 Stage 3 supercharged Roush?


  • This set of cams by Comp Cams would work on any 2005-2010 Mustang GT, even if it is supercharged. However, I'd recommend talking to a tuner or engine builder to pick out a good cam for your application since a large cam isn't always the best option for forced induction.


Helpful (1)

Forced induction? Will these cams work well with a supercharger pushing over 8+ pounds of boost?


  • Not ideal... There are better blower cams out there.


Helpful (1)

Would these cams work with an auto trans?


  • Yes. I have them in my 06 with an automatic trans. But I would recomend a 3000 stall converter.


Show 2 more answers Helpful (1)

Cams in everyday driver Can theses cams be used in a everyday driver without it being harsh on the motor


  • No problem with everyday driving. Good drive ability. Good power.


Show 2 more answers Helpful (1)

Couldn't the cam phasers be locked instead of limited for this cam?


  • While it is possible to lock the phasers it is not recommended as if it is not tuned correctly major engine issue could occur, the limiter kit is the safest and the most effective way to go with these cams.


Helpful (0)

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Customer Reviews (36) Write a Review

Overall Rating 4.9

out of 5 stars

Installation Time:Weekend

Installation Cost:$500-$1000

  • Performance Gain 4.388889 4.4
  • Fit 4.888889 4.9

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    July 28, 2012

    these cams are the way to go!

    I had these cams installed and absolutely love them, particularly when I pull in and leave car shows. Everybody is looking around to see where the camming hot rod is coming from and realize it is a newer mustang. I can't leave without getting stopped with questions and admiration. If you want to be the unique mustang at a show or just cruising around, these cams are the only way to go, believe me, I shopped around for a long time and I know I made the right decision.


    Year: 2008 Submodel: GT oregon

    Helpful (16)

  • 5/5

    Installation Time: Shop Install

    January 10, 2012

    Monster Sound!!!!!

    My local speed shop suggested these cams to me when I was serious about upgrading. At first I was a little disappointed when I realized I would have to buy the additional component (Phaser Limiter Kit) and some new camshaft bearings. I must say though, I am VERY pleased I went with these over the traditional Ford Racing cams. These may not be a direct fit like the Ford Racing cams are, but they are bigger cams with a sick sound to them and they increased my horsepower BIG TIME. My stang is now a beast thanks to these cams!!!


    Year: 2006 Submodel: GT South East Texas

    Helpful (15)

  • 5/5

    Installation Time: Full Day

    August 13, 2012

    Comp Cams breakdown.

    These cams are amazing!! They are a must for anyone looking for that extra power they are looking for in their S197. These cams have to have to meanest muscle car sound I have ever heard, i have got so many comments on this product that I'm starting to get annoyed! (In a good way) I had already put a full exhaust on my car so the outcome along with an offroad x pipe and catbacks make this thing sound so much more mean than it is! I would recommend this product to anyone looking for any HP gains what so ever. Thanks AM for making it easier to have a good time!


    Year: 2006 Submodel: GT Kentucky

    Helpful (7)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    June 29, 2012

    Great old school sound

    Very happy with this install. Great sound, great performance. Gave my 05 that great old school sound. I've had lots of compliments. Very glad I decided to get this mod. Would recommend this product to anyone thats looking for a great sound and increased performance. I give it a +A.


    Year: 2005 Submodel: GT Muscle Shoals, AL, USA

    Helpful (6)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    August 30, 2013

    Outstanding performance with supporting mods

    I just had these installed with 410 gears in my 08 GT and all I can say is WOW!! I can't say exactly what these cams gave me in horsepower numbers as I already had Pypes LT headers and ORX pipe, JBA axle back and Air Raid CAI installed when cam install was done. After dyno tune was complete, the car put down 363.94 rwhp and 342 torque at 6500 rpms. And did I mention that nasty lopey idle? Absolutely amazing!!! I Highly recommend these cams. And as always, AM came through again with very fast shipping.


    Year: 2008 Submodel: GT Newton, NJ, USA

    Helpful (5)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    August 25, 2012

    Comp Mother Thumper Cams

    These cams sound great and give the engine a whole new sound. I have enjoyed them so far!


    Year: 2008 Submodel: GT Maryland

    Helpful (5)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $250-$500

    April 19, 2013

    great choppy sound

    i only have stock exhaust anf a set of flowmasters outlaws axle backs installed with these cam and the car sounds amazing it sounds mean but isnt so loud u cant talk standing around it great buy for the money


    Year: 2007 Submodel: GT Gainesville, FL, USA

    Helpful (4)

  • 4/5

    Installation Time: Afternoon

    May 30, 2012

    My cam review

    The cams sound great in my mustang with the few intake mods i had already done. if you are a beginer to the mod world these cams are a really good way to start adding power to you mustang.


    Year: 2006 Submodel: GT Elgin IL

    Helpful (4)

  • 5/5

    Installation Time: Afternoon

    April 02, 2013




    Year: 2008 Submodel: GT MANY,LA

    Helpful (3)

  • 5/5

    Installation Time: Shop Install

    January 19, 2014

    Amazing sound that will turn heads

    I got these cams put in last week. I have moved, so i couldn't do it myself so I had a shop do it. Besides the ford shop messing up and have to have my car there two days these cams are amazing. I have a Bama tune with these cams and it ties it all together. Make sure if you buy these cams you get the phaser kit and two cam bolts, the bolts only come one at a time so make sure you get two. After It was all done, the whole shop came over to check out the sound. It sounds like a cammed out muscle car now and really sets my mustang apart. I would strongly recommend these cams from AM.


    Year: 2008 Submodel: GT St. Johnsbury, VT, USA/Seatte

    Helpful (2)

  • 5/5

    Installation Time: Afternoon

    June 22, 2017

    Amazing cam at an awesome cost

    These cams sound amazing and really wake the car up!!! They weren't hard to install at all. Make sure to get the cam phaser limiters as well. Great power, great sound and still able to drive it all the time.


    Year: 2007 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Full Day

    June 14, 2017

    WOW even if this is all I modded would be worth it

    These serious problems for me in my driveway, parking lots, garages, stop signs, traffic lights, "stop and go" traffic. And it's worth it, because the moment I'm above 2k rpm it is beautiful. I've learned to mitigate the issue I have below 2k rpm, no torque, stall issues. I embarrassed my wife by stalling 3x trying to park safely while taking her out to lunch. You can't go 20mph into a parking spot. Maybe once I finally finish my final upgrades and get a new tune it will be a sweetheart, that's ok, I wanted a beast and I have one.


    Year: 2008 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    May 26, 2016

    Amazing sound!!!

    I listened to a lot of videos on YouTube before and while I waited for the mother thumpr cams to arrive. I couldn't get over the sound difference in the videos. But that first time you fire it up and hear it you will smile ear to ear like the grinch that stole Christmas. Comp cams makes an amazing product and they do exactly as expected. You get a good little boost in performance as well as that nasty old school thump.


    Year: 2005 Submodel: GT

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    August 19, 2015

    Amazing sound

    Cams fit no problem, phaser kit was easy to install once we figured out how to get them apart. Awesome sound at idle little loss of power off the line (lag). Overall happy I chose these cams over the others.


    Year: 2010 Submodel: GT Milton, WA

    Helpful (1)

  • 5/5

    Installation Time: Full Day

    October 22, 2014

    Thumpn down the road

    I already had the Ford Racing "Hot Rod" cams in my Mustang, but I wanted more thump. I knew the Comp cams were only a little bit more that my Hot Rod cams, but I wanted to try them anyways. The Hot Rod cams are awesome, lumpy with great power, but the Comp cams changed everything. More power on the top end (which I knew) and hit's later (rpms), the only benefit is the huge cam lobe at idle. Would I switch back???, no can't beat the way everybody's heads turn when you drive up.


    Year: 2008 Submodel: GT Rathdrum, ID, USA

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    September 18, 2014

    Gallops Sitting Still!

    These cams are really great! They came packaged well and had all the grind specs, assembly lube and other documents in each cam box. Can't say much about the install. Had JPC in MD do the install as birthday present to me :p After the cams were installed, I noticed that my power brakes didnt work at idle and low RPMs because of low engine vacuum. I had to install a vacuum pump to have my power brakes properly work. These cams are worth the price just for the sound alone, not to mention the nice power bump you get in the higher RPMs. Get them!


    Year: 2005 Submodel: GT Westminster, MD, USA

    Helpful (1)

  • 5/5

    Installation Time: Weekend

    August 05, 2014

    Great set of cams!

    I purchased these cams with the FRPP intake manifold and I gotta say, the car sounds and performs fantastic now that they're running a little smoother with everything and the tune is getting dialed in. I did all the installs myself ( also installed the required Comp Phaser limited kit and new Phaser bolts that are both available from American Muscle ) The install wasn't TOO bad and I had never tackled anything that intensive on an engine before ( let alone on my daily driver ) and even though the install wasn't the worst thing to do, I think the peace of mind alone is worth the price of paying an experienced shop to do the install for you. Everything ended up fine in my case, but I can see how that could have ended very badly and you have no one else to blame but yourself haha Some other things you will need to complete this install if you're feeling brave and adventurous is a timing chain wedge and a bottle of cam assembly lube. American Muscle does not sell a timing chain wedge and the cheapest I could find one was from Freedom racing. And the lube can be purchased at any auto parts store. Other than that, you don't need to spend the money on a valve spring compressor. Just loosen the bolts on the cam caps one at a time working from the inside out to relieve valve spring pressure. Leave the roller followers in place when you remove the stock cams. But yeah, great cams, and great service from AM as always!


    Year: 2010 Submodel: GT Pontiac, MI, USA

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    July 28, 2014


    Great lope, really gives the car that sound of an old school hot rod. Felt the power gain right away, great bang for your buck. Had my shop do the install, took 7 hours to install, paid $700 for the install. And since you don't have to get new springs, you save even more money, a win, win situation. If you're looking for a great lope sound at idle than I highly recommend these Motha Thumpr cams.


    Year: 2005 Submodel: GT Austin, TX, USA

    Helpful (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $500-$1000

    June 13, 2013

    Good Power, Awesome Sound

    First the good: Fantastic sound either at idle or at full throttle. It will turn heads and people will give you the thumps up everywhere. Power increase is decent, but for max results install CAI, Motion Delete Plates, Headers, and exhaust. My results with all this was 350 RWHP / 338 RWTQ with an aggressive tune. You will see about 300-315 RWHP with no other mods but you still need a tune. The Bad: The car will sound great outside, but it may be a bit much for some people, especially if you drive it everyday. Since the build quality of these cars is not the best, you will hear more creeks and squeaks. You need to have at minimum a 3:73 Rear End Gear or car will buck or stall. You will be riding the gas constantly to get into gear. With an auto it may be different but mine is a manual. Fuel Econ goes down significantly, but you are probably not worried if you are getting these anyway. Overall I am very happy with them and AM had great delivery and service!


    Year: 2006 Submodel: GT Chicago, IL

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    May 23, 2013


    I have purchased these cams TWICE! I bought them and loved them enough to make them my first serious mod on my newest mustang.You will never ever regret doing business with American Muscle. They have taken exceptional care of me and treated me very fairly.


    Year: 2006 Submodel: GT

    Helpful (1)

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