GT500 5.4 Swap

serper3

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Hey guys, I am looking for options for pushing a lot of power in my 03 cobra. I am wondering how difficult it would be to get a Shelby GT500 short block in the car. I searched and wasn’t getting any results were people are specifically using the 5.4 out of the gt500. I am hoping to retain my heads, transmission, accessories and then of course upgrading to a 3.4 whipple or big kenne bell. The shortblock can probably be purchased for even cheaper through tousley ford, but Ford Racing Performance Parts - [Part Details].

What do you guys think? What problems with fitment/compatibility will I have? Would it be cheaper to just go with a MMR shortblock? I think it would be great if from the outside, with my stock valve covers, the motor would otherwise look stock. Thanks guys, I appreciate all the help an feedback.
 

lemosley01

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Build the shortblock. Install big-ass blower or turbos. Mix in nitrous.

The swap would be cool, and all, but IMO, don't hack up a good cobra for a project like this. Get a V-6 and do it that instead.
 

cobracide

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The way to go is 4.6 turbo for huge power - a lot easier. I'm really not understanding your goals. If it's just to get a 5.4 into a 03 then go for it. I agree that hacking up a cobra is a bit of a shame.
 
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HEMIHUNTER

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I was thinking the opposite myself. 03/04 cobra motor and tranny in a 05 and up non gt/gt500
mustang,make a good sleeper.Dont think the IRS would work though have to go solid
 

Badd Asp

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IMO the Ford Racing new 5 liter aluminum stroked to a 5.3 could easily be built to 800+ hp and much liter than the GT500 5.4 Fab would be much easier as the 5.4 is also wider than the factory 4.6
 

serper3

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sorry guys, let me elaborate on my goals better. I was looking to go whipple and run e85. hopefully, on the e85, i can push 700 whp or somewhere around their. the downside to e85 is that there are not too many stations around here etc. i would like to push that kind of power or more on pump gas, so it looks like that should be possible with the gt500 5.4. i know that my heads will bolt on the gt500, but i am wondering, if i will be able to retain my accessories and transmission. if this is the case, i should be able to easily attain my power goals, daily driveability, and still pass off as a 4.6 and be able to be close enough to ca emmissions were i can pass if i get reffed. what do u guys mean by hacking up a cobra? what would i need to do, do get the 5.4 shortblock like i linked in the op in my car? obviously i do not want to spend more money, and get less power lol. i am not trying to do this to simply say i have a 5.4 in my termi. i would rather be the opposite. drive like stock and run a whipple with a small pulley and push 750 whp.
thanks guys for your input, i hope u guys can confirm that these shortblocks are interchangable.
 

lemosley01

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What I mean by hacking up a Cobra is turning a limited-run Mustang into something else. You can do what you are looking to do to any V6 and no one will miss it. There aren't many Cobras of any year made.

How about a Whipple + Nitrous?
 

froggerlives07

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sorry guys, let me elaborate on my goals better. I was looking to go whipple and run e85. hopefully, on the e85, i can push 700 whp or somewhere around their. the downside to e85 is that there are not too many stations around here etc. i would like to push that kind of power or more on pump gas, so it looks like that should be possible with the gt500 5.4. i know that my heads will bolt on the gt500, but i am wondering, if i will be able to retain my accessories and transmission. if this is the case, i should be able to easily attain my power goals, daily driveability, and still pass off as a 4.6 and be able to be close enough to ca emmissions were i can pass if i get reffed. what do u guys mean by hacking up a cobra? what would i need to do, do get the 5.4 shortblock like i linked in the op in my car? obviously i do not want to spend more money, and get less power lol. i am not trying to do this to simply say i have a 5.4 in my termi. i would rather be the opposite. drive like stock and run a whipple with a small pulley and push 750 whp.
thanks guys for your input, i hope u guys can confirm that these shortblocks are interchangable.

Many guys push that kind of power with the stock 4.6. Nothing wrong with the motor you have.
 

serper3

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i know that this kind of power can be made especially with turbos. the problem is, the expense associated with these kits mixed with the unreliability of it, running race gas all the time and the emmissions i would much rather stick with a whipple, and not have to run race gas, and get the power with a more reliable short block. my motor also has 75k on the clock so i dont want to be driving around in a ticking time bomb. i think if i am pushing too much power from my motor, and i blow it up, i will likely swap it out for a forged short block or do something along the lines of what i am talking about here. i just dont want to have to end up redoing my setup in regard to fuel, or getting a bigger blower because that just wastes money. i would rather just get the stuff i need so i dont have to sell and buy new stuff down the road to handle the power level i want to be making.
 

i8urSS

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juiced46 just put a whipple 3.4 in his car and made 728 on pump gas with torco. i think that route would be alot cheaper than trying to make the 5.4 work. honestly i dont really see the 5.4 swap being cheaper than a turbo, and once your running the power levels your wanting to run theres always going to be issues. a 5.4 isnt going to just be magically safe. dont get me wrong. i'm not saying you shouldnt do what you wanna do. i just dont see it as the easiest or safest way to get the power your looking for. but whichever way you go, good luck
 

evil04svtcobra

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return fuel system, e-85, and 3.4l crusher, with nessesary mods = 700+ hp. on stock block, heads, cams, ect. no need to rip that 4.6 out!
 

serper3

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yea but if your going e85, even if i did that which i have been considering, the fuel system will be so expensive. 2.5k. fuel hat, fpdm, injectors, fuel pumps, lines etc. and then i am STUCK with running it. which i dont mind, but my whole goal is, if i can just spend 3100 on the shortblock, and then swap it into my car, and have it bolt in, i think it would be easier to run more power, on pump gas. if i wanted 800 whp, just smaller pulley and retune for 100 or torco mix...? i am just trying to figure out how difficult it would be to swap the short block. i can then price this build out, and price out going with a big whipple and supporting mods to push 700 on the stock short block. from there i can decide really what would be a better route.
 

SVTgsxrdude

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return fuel system, e-85, and 3.4l crusher, with nessesary mods = 700+ hp. on stock block, heads, cams, ect. no need to rip that 4.6 out!

+1 this is exactly what i would do

not the cheapest way to go but one of the best if your going for big numbers and thats if you dont want to go the twin turbo route IMO is a better way
 

GodStang

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return fuel system, e-85, and 3.4l crusher, with nessesary mods = 700+ hp. on stock block, heads, cams, ect. no need to rip that 4.6 out!

Yep.

I am well over 700 on 93 octane and have a tiny 2.8LH Behemoth. also the BEST PART of the GT500 is its heads. Getting the GT500 with out its heads is a complete waste!!!

Also someone with E85 hit over 700rwhp with a Whipple 2.3L.
 

CobraBob

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Contact Juiced46 (Dave) as he has had a few different power adders on his '03 Cobra. He really knows the potential of the 4.6 DOHC motor from the Terminator. He is happiest with the turbo setup, including the Whipple 3.4L Crusher he recently installed for a customer. Personally I see no point in wanting to put a 5.4 from the GT-500 in a Terminator. Especially we we know how potent the Terminator motor is. That is, unless you just want to try something different even if it ends up costing more and yields more issues that have to be resolved along the way. JMO.
 

Juiced46

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i know that this kind of power can be made especially with turbos. the problem is, the expense associated with these kits mixed with the unreliability of it, running race gas all the time and the emmissions i would much rather stick with a whipple, and not have to run race gas, and get the power with a more reliable short block. my motor also has 75k on the clock so i dont want to be driving around in a ticking time bomb. i think if i am pushing too much power from my motor, and i blow it up, i will likely swap it out for a forged short block or do something along the lines of what i am talking about here. i just dont want to have to end up redoing my setup in regard to fuel, or getting a bigger blower because that just wastes money. i would rather just get the stuff i need so i dont have to sell and buy new stuff down the road to handle the power level i want to be making.

This makes absolutely no sense at all. As far as emissions Turbo or SC it doesnt matter, its all going to test out the same. You are saying you need to run race gas all the time with a turbo its not true at all. Actually you can make MORE power with a turbo on pump then you can with an SC on pump gas. Next, you are talking about running E 85, so you dont need to worry about race gas anyway.

A 3.4 Whipple on a stock 4.6 DOHC can easily make 750-800rwhp. You can also do a turbo or TT setup and the sky is basically the limit. You can do a 5.4 swap, there is a bunch of custom stuff you will need to do to make it work. Its not worth it to me. Just stroke your 4.6 if you are worried about the cubes, but you dont need to do that either, put some ported heads on it and your power adder of choice. You can make 750rwhp on E85 all day, whether it be a Whipple, KB or Turbo and MUCH MUCH cheaper then it would to do a complete 5.4 build. There is alot more to it then just dropping the motor in. Also if you cant run E85, and you are worried about needing race gas. I have one word that will cure that problem METH.
 

serper3

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Sorry, yea I mixed my thoughts there and it didn't make sense. I know that turbos don't need race gas gas because its easy to turn the boost down and run w.e gas and boost you want. They also make more power because they have lesss parasitic loss... i know. What I meant to say, was that. With the 5.4 u don't need race gas to run the same amount of power. I guess today I have been finding out though that my heads won't make gt500 power with the gt500 block because the heads on the 500 are much better..

As far as making 800 whp, on the stock motor, with the 3.4 it looks like its possible, and it is easy for the whipple to make thatt like you say, but that is really pushing the stock motor. I spoke with aed today were I plan to get my work done, and they strongly advise against pushing over 700 whp out of the stock motor. This is understandable though, they have a reputation to hold, they don't want the motors they tune to blow up.
Can you please explain what other things need to be done besides dropping the 5.4 in? What's not going to directly bolt up?
 

serper3

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Sorry, yea I mixed my thoughts there and it didn't make sense. I know that turbos don't need race gas gas because its easy to turn the boost down and run w.e gas and boost you want. They also make more power because they have lesss parasitic loss... i know. What I meant to say, was that. With the 5.4 u don't need race gas to run the same amount of power. I guess today I have been finding out though that my heads won't make gt500 power with the gt500 block because the heads on the 500 are much better..

As far as making 800 whp, on the stock motor, with the 3.4 it looks like its possible, and it is easy for the whipple to make thatt like you say, but that is really pushing the stock motor. I spoke with aed today were I plan to get my work done, and they strongly advise against pushing over 700 whp out of the stock motor. This is understandable though, they have a reputation to hold, they don't want the motors they tune to blow up.
Can you please explain what other things need to be done besides dropping the 5.4 in? What's not going to directly bolt up?
 

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