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Ford Performance Turbo-Swirl GT40X Aluminum Head - 58CC Chamber (82-85 5.0L; 87-95 5.0L)

AmericanMuscle no longer carries the Ford Performance Turbo-Swirl GT40X Aluminum Head - 58CC Chamber (82-85 5.0L; 87-95 5.0L). Please check out 1979-1993 Foxbody Mustang Cylinder Heads & Valvetrain Components for an updated selection.
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Features, Video & Details

  • Bolt on 65 More Horsepower
  • Improved Air Flow Over Original GT-40 Heads
  • Combustion Chamber Volume 58cc
  • Intake Port Volume 178cc, Exhaust Port Volume 62cc
  • Lightweight Aluminum
  • Fully Assembled
  • Fits 1982-1985, 1987-1995 Windsor-Style 5.0L V8s
  • Sold Individually

Review & Installation Video

Review & Install Video

Hey guys, Stephanie from Here with the review of the Ford performance GT40x aluminum heads with the 58 CC combustion chambers for 1982-85 and 1987-95, 5 liter Mustangs. The Ford performance turbo swirl heads with the 58 CC combustion chambers are going to be for the 5 liter owners out there that are looking for a fully assembled aluminum head with a smaller combustion chamber in order to keep a higher compression ratio. The turbo swirl heads offer a ton of upgrades over the factory set up and the heads are the main component that flow air and fuel in and exhaust gases out, so they have a big impact on performance. There's a lot to go over here with these heads, but picking which cylinder head to add to your build isn't an easy task. Bigger isn't always better. You wanna choose the head that will be best for your application and your build. These heads not only have improved air flow over your factory heads, but they also have improved air flow over the original GT40 heads. If we look at the main components of the head, we're going to look at the combustion chamber first and its' volume.These particular heads have 58 CC combustion chambers. The volume of the combustion chamber is tied to the compression ratio and displacement, which is tied to horsepower. A larger chamber means larger displacement. A smaller chamber will increase the combustion ratio because you're compressing the same amount of air in a smaller space. If we compare these heads to the other Ford performance offering, these heads have 58 CC chambers, while the other option has a 64 CC chamber. That means that these heads which flow the exact same amount as the other Ford performance heads, will give a higher compression ratio, all other things equal. That's something that you want to keep in mind when you're planning your build. The next thing I'll talk about is the intake ports and then the exhaust ports. The intake ports are fed air and fuel through the intake port runners, and each port will match up to an intake or an exhaust belt. Of course, larger ports can flow more, and these heads have an intake port volume of 178 CCs and exhaust port volume of 62 CCs. What you usually want to do when you're picking out a set of heads, is to match your intake port type on the cylinder head to an intake manifold with a similar shaped port because the air is going to flow through the intake to the ports on the heads and you want smooth airflow here. That being said, just make sure you have the manifold lined up that'll work well with these heads. As far as the exhaust ports, you're going to want to make sure that the headers are larger than the exhaust ports on the head and that the gasket can seal well. That leads us to the intake and the exhaust valves. Once again, the larger the valves, the more air and fuel and exhaust can be flowed. These heads are matched for 1.94 intake and 1.54 exhaust valve diameters. Exhaust valves are smaller than intake valves, so don't take that as a negative sign. The intake valves are larger because of the way the engine works. It creates a vacuum to pull the air and fuel in, which isn't as efficient as pushing the exhaust out. So, the intake valves need to be bigger to compensate for that. Technical things aside, these are aluminum heads. Aluminum heads are light weight. These are 22 pounds each. That's 25 pounds lighter than the original cast iron GT 40 head, which will make for a total weight savings of 50 pounds. The other thing about these heads is that they're fully assembled. They come with the intake valves, exhaust valves, and valve springs. The valve springs are compatible with all Ford performance roller cam shafts too. Just so you guys know, when you're picking out your other build parts. When it comes to spark plugs and rocker arms, there are specific product numbers listed on the product page, but you can run with the 1.6 ratio or a 1.7 bolt down rocker arm with these heads. When it comes to price, these heads are sold individually and you're looking at $600 per head. The 64 CC chamber option costs the same, and the Ford performance heads are less expensive than the Ettlebrock options that are on the site. As far as the install, this is a difficult install and it's a three out of three wrenches in the difficulty meter. This isn't a job for someone that doesn't have much experience under the hood, and you're going to need your toolbox to get the install completed. Looking at breaking down the top end to get the install completed, so about a days work and unless you're experienced in this art and you can break a top bend down in a short amount of time. You're looking at breaking down the intake manifold, so you can completely pull it from the car. The valve covers, you'll have to pull the distributor to pull the lower manifold, all the front end accessories that bolt to the heads. You got to pull the rockers and push rods from the heads and finally drop the header so you can unbolt the heads and pull them free from the block. Once you're down to the short block, you have to clean up the block before installing your new head. So, remove the gaskets and get the block clean. After that, you can install your new heads, reinstall the lifters, push rods, and rocker arms if you didn't pick up a new set and reinstall all other parts that you broke down to pull the heads. Wrapping things up here with the Ford performance turbo swirl GT40x heads. These are aluminum heads with 58 CC combustion chambers. They come fully assembled. They offer improved air flow. They're lightweight and you can check them out more online right here at

More Power. Increase the horsepower and torque output of your push rod 5.0L engine with the Ford Racing Turbo-Swirl GT40X Aluminum Head. These GT-40X heads feature a 58CC Combustion Chamber to greatly improve the airflow over the original GT-40 design allowing you to bolt on 65 more horsepower.

Improved Air Flow. These Ford Racing GT-40X heads have an intake port volume of 178cc allowing for an intake flow of approximately 240 cfm at .550" lift (at 28" of H20) and an exhaust port volume of 62cc allowing for an exhaust flow of approximately 170 cfm at .500" lift (at 28" of H20). Machined for 1.94" Intake and 1.54" exhaust valve diameters.

Lightweight. Made from high quality original equipment style 356-T6 aluminum castings, each head weighs in at only 22 lbs. that is 25 lbs. lighter than the original cast iron GT-40 head, that is a weight savings of 50 lbs.

Fully Assembled. Leak tested prior to assembly, each Ford Racing Turbo-Swirl GT40X Aluminum Head comes fully assembled with M-6507-J302 intake valves, M-6505-G302 exhaust valves, and M-6513-A50 valve springs. As an added bonus the valve springs are compatible with all Ford Racing roller camshafts.

Installation Notes. Ford racing "X" heads are designed to use either GT-40 or aftermarket performance intake manifolds, M9439A50 intake gasket, and AGSF-32C spark plugs. Designed for bolt-down rocker arms part number M-6564-B351 for a 1.6 ratio or use part number M-6564-A50 for a 1.7 ratio.

Application. The Ford Racing Turbo-Swirl GT40X Aluminum Head is designed to be a direct bolt-on for the 1982-1985 and 1987-1995 5.0L Windsor-style V8 engines. It will not fit 1986 5.0L with flat-top pistons unless pistons are notched for valve relief.

Technical Note. Be sure to check your intake manifold for port match, because not all intakes are compatible due to the tall high-flow ports.

Fitment: 1982 1983 1984 1985 1987 1988 1989 1990 1991 1992 1993 1994 1995 Details

MPN# M-6049-X307

CA Residents: WARNING: Cancer and Reproductive Harm -

What's in the Box
  • (1) Assembled cylinder head
Installation Info
Tech Specs
Will it fit my Mustang?
  • Cobra - 94, 95
  • Cobra R - 95
  • GT - 87, 88, 89, 90, 91, 92, 93, 94, 95
  • LX - 87, 88, 89, 90, 91, 92, 93
  • Other - 82, 83, 84, 85

Fits 5.0L Ford V8 engines. It will not fit 1986 5.0L with flat-top pistons unless pistons are notched for valve relief

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Questions & Answers (24)

5 Top Rated Questions

I want to install these on my 90 LX, 5spd. Just need to now if they are smog legal!

  • Hi, These GT40x heads are not smog legal.

Helpful (1)

I want to buy these heads for my 1994 Mustang Cobra. Can I reuse the stock 1994 Cobra intake with these heads? Thanks in advance, Zach

  • The Ford Performance Turbo-Swirl GT40X Aluminum Head- 58CC Chamber will be compatible with the factory 1994-1995 Cobra upper and lower intake manifold.

Helpful (0)

Are these heads interchangeable, will they fit on either side?

  • The Ford Performance Turbo-Swirl GT40X Aluminum Heads in the 58CC Chamber will be for driver or passenger side fitment.

Helpful (0)

Is there an intake that works best

  • The Ford Performance Turbo-Swirl GT40X Aluminum Head will work well with a number of intake manifolds, depending on the remainder of your setup. Cam selection, and exhaust, as well as desired RPM range will have a great influence on what intake will work best with these heads in your build.

Helpful (0)

will this heads fit a 1995 cobra 5.0L? I will be using the stock 1995 cobra intake

  • The Ford Performance Turbo-Swirl GT40X Aluminum Head will fit a 1995 Mustang Cobra 5.0L Engine.

Helpful (0)
Post Your Question
10 More Questions
Hi if I purchase these will they work with my long tube headers of do I need special ones 1 answer
I plan on restoring my motor and including these heads, but I don't know what other parts I may need. What cam, pushrods, roller rockers, and intake manifold do you recommend? I have a 1995 GT 5.0 Thanks. 1 answer
I was thinking of buying a set of these heads and was wondering if I would need new rockers if I would be putting them on a stock '94 mustang gt, and if I do, which would be recommended. I was also wondering if I would need new push rods for these heads or if the factory push rods would work. 1 answer
Will these heads work with a stock flat tappet cam , hooker long tube headers and a carbureted edlbrock performer intake manifold in an 85 Mustang GT as a direct bolt on . Also has a non H.O. Firing order . Thanks ? 1 answer
I saw in the review a person needed a shim kit for their rockers is this true for all rockers? I am running a comp xenergy stage 2 cam with comp 1.6 rockers and don't want to end up with valves that do not fully close. 1 answer
have a 86 20thou over carbed 351w with a mild rv cam in a AC cobra replica...would these be a good addition for this motor...running stock iron heads now...if yes what would also recommended for these heads(intake,cam,etc.) thanks steve 1 answer
Both heads for $600 ? 1 answer
Will this head work on a 89 5.0 with a b303 cam and stock Legnth pushrods and 1.6 roller rockers with a 3/8" stud. 1 answer
Hi. I'm planning to install these heads on a 85 302. The engine has a B-303 cam in it. I'm also plan to install Crane 1.7 rollers in it. Will this work ? Thanks. HT 1 answer
Would this fit an 86 gt? 2 answers

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Customer Reviews (3) Write a Review

Overall Rating 4.3

out of 5 stars

Installation Time:Afternoon

  • Performance Gain 4.666667 4.7
  • Fit 4 4

  • 5/5

    Installation Time: Afternoon

    February 27, 2018

    Great heads

    Great head and good power gain through the power band very nice head for the price thanks AM..


    Year: 1987 Submodel: GT

    Helpful (7)

  • 3/5

    May 19, 2017

    GT40X Heads

    I am a Ford Mustang fanatic!!! I have installed the GT40X Aluminum Heads-58cc on my 89 Fox Body, I am a bit annoyed with the fact that Ford milled the bottom of these heads to much that you have to buy a shim kit for your roller rockers to perform properly so that the valve will open and close to build up compression to start the engine. Sad that Ford didn't test this issue when designing these heads. These heads are suppose to be a direct bolt on with no issues as advertised everywhere!!! So waiting on the shim kit to get my Fox back on the strip!! Thanks American Muscle for having "Jeff" that is very knowledgeable on this problem and helped us out!!!


    Year: 1989 Submodel: GT

    Helpful (9)

  • 5/5

    Installation Time: Full Day

    January 16, 2015

    Ford Racing GT40X heads

    Ready to rock right out of the box with no additional parts needed besides gasket and head bolts. Direct bolt on for my 95 cobra 5.0 and worked with the factory 1.7 roller rockers. Felt the power instantly, can't wait to get it to the Dyno and see what the numbers say. Great product and made it to my doorstep super fast like always. Thanks AM


    Year: 1995 Submodel: Cobra La Vernia, TX 78121, USA

    Helpful (9)

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