Ok guys i am sure that this question has been asked/answered but since i am new i would like to pose it again. I currently have a 1999 cobra with several bolt ons. yes cobras are nice unique and i love mine but it does not have enough umph. i also do not want to go the obvious routes via n02, sc, turbo, though i love all options and all get to the overall power goal i just think there is something to be said about a 5.4 dohc 1999 model cobra. My question is if i where to get a 5.4 shortblock would my heads/intake fit??? would all the coolant passages, bolt holes ect line up. if so then the obvious front accessaries would need to be borrowed off of what i would think would be a gt500/cobra R. as well as a custom tune. has this been done and how will i accomplish this task?:shrug:
99 Cobra to a 5.4 DOHC
- Thread starter 19blkcbra99
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After doing a little research it looks like the navigator came with the 5.4 dohc motor for several years. from the factory it did not produce mauch power and would really like to used the top end of my car. any suggestions???
Yeah Birdman has a Badass 5.4 Stuffed into his engine bay, it can be done the
Cobra R's had em..
Cobra R's had em..
You can make this swap as easy or as difficult as you want....
The Navigator motor in a Navigator didn't make much power because of the truck intake and restrictive exhaust. When you install it in a mustang with a better intake and a free flowing exhaust, you'll be good to go. You could also use your cobra heads/cams, they flow a bit better and are designed for higher RPM power, rather than low RPM torque.
Since the 5.4 is wider than the 4.6, your intake won't fit.The 5.4 can be a bolt in deal, the hard part is finding an intake you want to use. Depending on the intake, all your factory electronics will work, and all you'll need is a new tune, and perhaps a new hood.
KarKraft makes adapter plates so your 4.6 intake will work on the 5.4. That would make the switch the easiest, so you don't have to mess with fuel rails, injectors, throttle body location, etc. etc. etc. The only thing is that the adapter plates aren't the best for performance.
There are a few other intake options available, such as the sullivan spider intake, and the australian "boss" intake that came factory on the 5.4 DOHC Falcon Sedans down there. You could also try to find a GT500 instake setup and front dress..
I'll let birdman chirp in and explain some better details about the swap.
Homer
The Navigator motor in a Navigator didn't make much power because of the truck intake and restrictive exhaust. When you install it in a mustang with a better intake and a free flowing exhaust, you'll be good to go. You could also use your cobra heads/cams, they flow a bit better and are designed for higher RPM power, rather than low RPM torque.
Since the 5.4 is wider than the 4.6, your intake won't fit.The 5.4 can be a bolt in deal, the hard part is finding an intake you want to use. Depending on the intake, all your factory electronics will work, and all you'll need is a new tune, and perhaps a new hood.
KarKraft makes adapter plates so your 4.6 intake will work on the 5.4. That would make the switch the easiest, so you don't have to mess with fuel rails, injectors, throttle body location, etc. etc. etc. The only thing is that the adapter plates aren't the best for performance.
There are a few other intake options available, such as the sullivan spider intake, and the australian "boss" intake that came factory on the 5.4 DOHC Falcon Sedans down there. You could also try to find a GT500 instake setup and front dress..
I'll let birdman chirp in and explain some better details about the swap.
Homer
X3. He knows all about doing this. It is a lot easier to throw a power adder though.....
Karkraft went out of business. 
This topic is interesting to be me because I'm doing the same swap right now. I picked up a 5.4 DOHC Navigator longblock last week.
If you don't mind, I also have some questions to ask:
I saw that some people have taken the Navigator intake, removed the upper and welded their own sheet metal box like upper intake onto the lower intake. How does this compare with using my 01 intake w/ adapter plates? Will I not have enough hood clearance? That's my biggest issue.
Second, right now my Cobra spins at 7k rpms. This is a different engine. What do I need to do to to be able to rotate that fast again? I was thinking about swapping my current cobra heads on, but I'd prefer not to for other reasons (like keeping a fully functional cobra longblock for possible swaps).
How is the navigators lower end also? How stout is it? Can it handle any forced induction?
Oh and if it helps people answer my question at all, I'm planning on adding forced induction in the future, but want to swap it N/A first to take little steps at a time.
Thanks.
This topic is interesting to be me because I'm doing the same swap right now. I picked up a 5.4 DOHC Navigator longblock last week.
If you don't mind, I also have some questions to ask:
I saw that some people have taken the Navigator intake, removed the upper and welded their own sheet metal box like upper intake onto the lower intake. How does this compare with using my 01 intake w/ adapter plates? Will I not have enough hood clearance? That's my biggest issue.
Second, right now my Cobra spins at 7k rpms. This is a different engine. What do I need to do to to be able to rotate that fast again? I was thinking about swapping my current cobra heads on, but I'd prefer not to for other reasons (like keeping a fully functional cobra longblock for possible swaps).
How is the navigators lower end also? How stout is it? Can it handle any forced induction?
Oh and if it helps people answer my question at all, I'm planning on adding forced induction in the future, but want to swap it N/A first to take little steps at a time.
Thanks.
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awesome that somboody else is in the same boat i am in. trying to tackle a 5.4.
IMO i DO NOT know the actual specs of cams/heads but i would think that the navigator heads/cams would not produce the hp comparing to a set of cobra heads/cams.
If anyone knows for sure please chim in as i will be faced with this same question when i purchase my engine.
IMO i DO NOT know the actual specs of cams/heads but i would think that the navigator heads/cams would not produce the hp comparing to a set of cobra heads/cams.
If anyone knows for sure please chim in as i will be faced with this same question when i purchase my engine.
Navi's used the same 184 degree itnake cams as the mach 1, 03/04 cobra, maruader, avaitor and mark 8s. Even with Cobra cams the 5.4s power will peak at a very low rpm. I recommend a low intake LC and no less than 220 degrees duration to malke decent power on the street. With the stock cams the 5.4 maakes for a great auto trans powerplant, but not a good on for a manual trans car.
The navi heads have larger ports than the 4.6 C heads, 4.6 C heads will bolt right up and with adapers you can use the cobra intake.
Intakes:
-A cut Navi intake with a box upper stinks, it's an awful intake design and the power they make is pitiful.
-The Sullivan intake is a great intake if you plan to spin the engine above 7k.
-The Aussi Boss intakes are great, but costly
-The GT intakes will not fit the Navi heads
This swap can be done for little expense and very little power has to be compromised to get get it done.
Birdman is the guy to talk to about what has to be done to make the swap simple.
The navi heads have larger ports than the 4.6 C heads, 4.6 C heads will bolt right up and with adapers you can use the cobra intake.
Intakes:
-A cut Navi intake with a box upper stinks, it's an awful intake design and the power they make is pitiful.
-The Sullivan intake is a great intake if you plan to spin the engine above 7k.
-The Aussi Boss intakes are great, but costly
-The GT intakes will not fit the Navi heads
This swap can be done for little expense and very little power has to be compromised to get get it done.
Birdman is the guy to talk to about what has to be done to make the swap simple.
i found his thread on mach1registry and it does sound doable. but how would i get ahold of this nirdman? is he a member of this group???
The other intake option is to see if you can find a GT500 lower intake and blower assembly as well as the front accessories. It's definitely not the least expensive or the easiest, but at least you'll get a blower out of the deal.
Homer
Homer
Yeah i agree but trying to explain putting a new engine in a car that she already hates in adition to the fact that i just had a forged engine built.
Maybe if i won the lotery.....any one have any winning tickets they might share????:beer:
Birdman941
search for him on here and send him a PM, I am sure he will be more than willing to help you with the 5.4 swap.
I am looking to go that way possibly this summer..it is very doable and he has been able to do the complete swap in a weekend's time.
He sells a swap kit that will allow you to retain your a/c, keep the engine positioned properly in the engine bay with k-member spaces, as well a bunch of other things that allow the 5.4 to just drop in! and has the extremely difficult to find aussie 290 intake manifold.
You can take a navi shortblock..your cobra heads and 96-98 cobra cams with the aussie intake and it will be a combo that will produce a good amount of power and low-end torque..something these 4.6L dohc lack.
I suggest getting the heads decked [to reduce the chamber size] or getting custom pistons made to raise the compression.
but yea..just PM the man and he'll explain everything!
search for him on here and send him a PM, I am sure he will be more than willing to help you with the 5.4 swap.
I am looking to go that way possibly this summer..it is very doable and he has been able to do the complete swap in a weekend's time.
He sells a swap kit that will allow you to retain your a/c, keep the engine positioned properly in the engine bay with k-member spaces, as well a bunch of other things that allow the 5.4 to just drop in! and has the extremely difficult to find aussie 290 intake manifold.
You can take a navi shortblock..your cobra heads and 96-98 cobra cams with the aussie intake and it will be a combo that will produce a good amount of power and low-end torque..something these 4.6L dohc lack.
I suggest getting the heads decked [to reduce the chamber size] or getting custom pistons made to raise the compression.
but yea..just PM the man and he'll explain everything!
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The thread on the Mach 1 Registry is up and running again.
[ame="http://www.mach1registry.org/forums/showthread.php?t=57118"]Link[/ame]
It is pretty long but has a lot of pics.
I also have a thread here on SVTP. Link
The 5.4 32V pretty much drops right in.
Aside from mine, there are several others out there using the "kit".
It allows you to keep your AC and accessories.
The Aussie Boss intakes are perfectly suited for this swap.
Many ideas for this actually came from Al Papitto,
who did this swap 10 years ago, before the 2000 Cobra "R" was born.
I modify the upper manifold to work on Mustangs,
but it looks like factory.
Any questions members might have, feel free to send a PM.
Subbing this thread also.
Cheers!
[ame="http://www.mach1registry.org/forums/showthread.php?t=57118"]Link[/ame]
It is pretty long but has a lot of pics.
I also have a thread here on SVTP. Link
The 5.4 32V pretty much drops right in.
Aside from mine, there are several others out there using the "kit".
It allows you to keep your AC and accessories.
The Aussie Boss intakes are perfectly suited for this swap.
Many ideas for this actually came from Al Papitto,
who did this swap 10 years ago, before the 2000 Cobra "R" was born.
I modify the upper manifold to work on Mustangs,
but it looks like factory.
Any questions members might have, feel free to send a PM.
Subbing this thread also.
Cheers!
Thank you very much Birdman for willing to help newbies tackle this swap. I'm going to start mine soon.
I want to learn more about the 5.4 DOHC Navigator engine I picked up. My ultimate goal would be to not molest my current 4.6 DOHC Cobra engine much (I know oil pan and other things are required to swap, but more along the lines of the heads), and drive the navigator engine like I am used to driving my cobra (redline 7k etc.). I'm a bit ignorant though when it comes to this as I'm not sure what actually limits the engine from revving... I know if it rev's too fast, the valves can not close fast enough and start tapping the pistons, but springs should fix that.
As far as intake, after hearing about the poor performance of the sheet metal upper/navi lower, I'm going to just use my 01 cobra intake with adapters.
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has anyone else done this swap. if so what route did they take and how did it turn out.
i am curious to see how many have actually tackled this project.
i am curious to see how many have actually tackled this project.
Naples, Florida (My buddy's car)
My car
Jordan ( car in Mn. in process)
Al Papitto's Black Cobra (459 RWHP)
My car
Jordan ( car in Mn. in process)
Al Papitto's Black Cobra (459 RWHP)
Awesome pics! Whoa, what's that intake on the last picture??
Homer
Homer
Al is using a prototype 2000 Cobra R manifold.
Very rare.
Very rare.
Thanks Birdman, I really appreciate all your contributions to this forum.
What front cover is being used on these swaps? Navigator? Australian Ford Falcon? GT500? Or is the front cover a "custom" version made from the 5.4 bottom V and the 4.6 top parts? Does it matter?
Homer
What front cover is being used on these swaps? Navigator? Australian Ford Falcon? GT500? Or is the front cover a "custom" version made from the 5.4 bottom V and the 4.6 top parts? Does it matter?
Homer
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