2004 Mustang gt

PhillyCheeseCake05

New Member
Jan 4, 2021
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Milpitas, ca
Hi, im new at fixing cars but i wanted to know if i could install a 2003-2004 mach1/cobra intake manifold on a gt engine?? Any info will be greatly appreciated before i spur of the moment go on a buying craze. If they’re not compatible, why? Also i just changed my shocks N struts n its driveable but whenever i hit a dip or road is slightly uneven i hear a “kadunk” from the rear. I bought my car used and to looks the the previous owner just piece random parts together to get it running before he sold it to me. Rather than cryin bout how the scumbag ripped me off, i slowly started giving it so tlc it much needed but not sure if im doing thing correctly.
 
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tsemmett

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Jul 2, 2019
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No, they're not compatible. The Mach 1/Cobra 4V head is completely different; the intake ports are much larger, and the spark plugs aren't along the intake port face like they are with the 2V GT engine. Do a Google Image search for both "4.6 4V C Head" and "4.6 2V PI Head" and you can see the difference.
 
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PhillyCheeseCake05

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Jan 4, 2021
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Milpitas, ca
Thank you very much for that explanation. I guess my only option would be to upgrade my engine to a cobra engine so my new throttle body and cai isnt a waste of money. Does anyone know what i would need additionally to swap from a 04 gt to a 2002-2004 cobra engine? Or will it be removal of old engine n just drop in the cobra? I know i would need a new tranny but any other parts required to do the swap so i can do a total estimate of what it would cost me. Thanks for your help. I love my stang but wish i haggled the crappy previous owner so i could use that $$$ to give her the proper love she needs.
 

tsemmett

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Jul 2, 2019
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Physically, a 4V engine is a direct bolt in. Electronically, you'd have to modify your 2V harness to fit it (it has the same basic electronics, but they're not all in the same location). You do not need a new transmission.

What is your goal for you car? If you're just looking to be a bit faster, modifying your 2V might make more sense. If you're looking to be a lot faster, boosting your 2V may also make more sense.
 

PhillyCheeseCake05

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Jan 4, 2021
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Well at first i was thinking of a swap to cobra engine but cost wise its out of my reach for now. Wasnt planning on upgrading anything at first but since she needed some tlc n it being my daily i started buying new parts. Brakes/rotors/starter/coolant reservoir/battery/push start/cai/throttle body/shocks n struts/injectors/tuner/waiting on supercharger until i can find a second hand one for decent price. Wasnt thinking when i bought some of the items cause they werent compatible with my engine (ie. Cai n throttle body were meant for the cobra spent 400) i seen cobra engines in the ranges 3500-9000. Cost wise i was hoping i could have put the cobra/mach one intake manifold onto my gt so i could use the cai n throttle body i already purchased without having to do a whole swap until my engine craps out. Adding what i spent n will need to spend is rounding near getting engine swap. Honestly i just enjoy driving her. Not too big on gains but wouldnt mind if she able to put some cars in their place. Lol! i could go w/ either option cause i really wanted a cobra but cant afford one or save myself the trouble n just mod the gt. Which one is worth the money? Is there a significant difference in power n speed between the two? I can post pic later. I seen on ebay a trickflow intake manifold that would fit the gt n accommodate my cai n throttle body for another 800.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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Massachusetts
Larger throttle body and plenum are two effective ways of getting some additional HP from a 2v GT
 

PhillyCheeseCake05

New Member
Jan 4, 2021
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Yeah, i have the trickflow 70mm throttle on currently but i really had my hopes on being able to get my accufab twin throttle body on somehow. From what i’ve been hearing is motor swap if i want to be able to use it, cut my loss n try n resell, or getting trickflow billet intake manifold 2v which would be able to fit the throttle body perfectly i think just not sure if it would fit my motor. Spending another 500-800 Vs motor swap seems ideally more realistic in my financial condition. I could cut my losses n resell the parts cause im happy with how she performs when i put the pedal to the floor. Makes me grin every time.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
36,189
12,098
224
Massachusetts
No reason to try and squeeze the twin TB on if you have a stock intake/plenum. If you had the trick flow plenum you could use it, but that's a $1k for that for materials to install.

At the end of the day, the cost and time of doing a 4V swap might be more expensive than just modifying your 2V. TB/Plenumn, long tubes, h-pipe and cat-back, and even a set of cams might put you at the same power level as a N/A Cobra, at a cheaper price (if you find the parts cheap, second-hand). If you still want a 4V engine, might be better of selling our car and buying one. 96-98 Cobras can be had for $5-7K.

As someone who's swapped engines, and removed and built a few, you can take your budget, and double it. If you think you can do it for $4K, it will be closer to $8K. All the little odds and ends you don't account for add up. A bracket here you need, a hose there. $50 there, $100 here. Seeing your clutch, and deciding "while i'm here". Stripping a hole out in the flywheel, things like that. Coolant, supplies, etc etc. Scope creep is a real thing unless you cut corners.
 

PhillyCheeseCake05

New Member
Jan 4, 2021
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Milpitas, ca
True, I appreciate your advice. Yeah i think i’ll stick to my 2v until it blows then upgrade to a cobra engine but for now im content with how she performs. Wouldnt mind the extra power n speed tho. Haha! Just trying to get a smoother more comfy ride now rather than fell every pot hole/dip on my commute. Thanks everyone who help me figure this out.
 

stormsedge

Active Member
Jun 17, 2018
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Here
Hi, im new at fixing cars but i wanted to know if i could install a 2003-2004 mach1/cobra intake manifold on a gt engine?? Any info will be greatly appreciated before i spur of the moment go on a buying craze. If they’re not compatible, why? Also i just changed my shocks N struts n its driveable but whenever i hit a dip or road is slightly uneven i hear a “kadunk” from the rear. I bought my car used and to looks the the previous owner just piece random parts together to get it running before he sold it to me. Rather than cryin bout how the scumbag ripped me off, i slowly started giving it so tlc it much needed but not sure if im doing thing correctly.
Regarding the 'kadunk". Check your shock fasteners...likely one was left a bit loose when you changed them. Double check anything else you removed or loosened while under there.
 

tsemmett

Active Member
Jul 2, 2019
265
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Supercharger or turbocharger?
I would suggest at least a $5k budget, assuming you can do the work yourself. I priced an On3 Turbo and Torktech supercharger setup, and both came up a hair over $4k by the time you buy the required supporting parts, but that didn't include tuning. You could potentially shop around and buy used parts cheaper, of course.
 

PhillyCheeseCake05

New Member
Jan 4, 2021
9
0
1
36
Milpitas, ca
I think im going to get a trick flow intake manifold so i can install the twin jet throttle body and cai that i have already purchased before i did any sort of research. I know, stupid of me but its too late to turn back now. I believe that intake manifold should be compatible with my 2v engine. I also came across another issue as i hooked up my tuner i got some codes it read codes P0304 and P0316. I read its a misfire in cylinder 4 and the other misfire in the first 1000 revolution. Im assuming if im able to fix P0304 issue it should clear the other code as well seeing as it goes hand in hand (hopefully). Instead of bringing it to the shop i wanted to try n fix it myself so if i ever have this issue again i know if i would be able to fix it on my own. So over the weekend i plan on taking coil n spark plug on cylinder 4 and swap them on a different cylinder and see if the codes change to reflect if the spark plugs and/or coils need to be replaced. If the codes stays constant then i think its an issue with my valves or timing n i would have to take off my valve covers and check the spacing n adjust to the proper specs. My question is would anyone know the cylinder diagram and specs i would need to space the valves if needed. Thanks again