5.4L DOHC Conversion Questions (need feedback)

BlackenedSVT · Dec 8, 2005

So i think this summer i am going to make a new project for myself, and i would like to convert my regular 4.6L SOHC Mustang (mods in sig) into a 5.4L DOHC "Cobra R" powered car.

Has anyone ever done this swap? Can anyone give me anyinformation about this swap? The more detailed the better. I ONCE saw someone put a 5.4L SOHC Lightning engine in a 94-98 Model GT and i know the engine was sticking out of his cowl hood. It was too tall and they had to cut out the top of the hood. ....I do not want to do that with my car, but im pretty sure everything will fit in my 2002 GT.

Please note that i will be doing all of the work on this car myself (i'm a learning mechanic in technical school), and will get some professional mechanical help if need be. I have also done all of the modificaitons in my sig by myself BEFORE i even attended technical school. So i think i'm mechanically enclined enough to do this engine swap.

Here is the engine i was thinking about, from here:

http://www.karkraft.com/long_blocks.htm

Precision built 5.4 4 valve long blocks

Replacement for 5.4 Navigator or retro a clone Cobra "R" in a Mustang.

uses seasoned cast iron Windsor block, 8 bolt steel crankshaft, new Ford OEM hypereutectic pistons and Ford rods. Complete with new cams, chains and timing cover as shown. fits 99/03 Navigator. please specify year when ordering.

$3195.00 #KK6006NV truck freight only

Ok, now down to the nitty-gritty. What else will i be needing with this motor?

Off the top of my head i can gather this:
- New flywheel & Transmission & driveshaft (T-56 Cobra would be ideal)
- upper and lower intakes (can i use Navigator parts?)
- water pump, alternator, pulleys, hoses, etc
- valve covers
- a new Hood (probably the Cobra R hood of course)

What other parts would i be in need of?

If you had to guestimate, how much do you think this swap would run me, excluding labor...strictly parts & shipping if need be

I'm guessing that the 5.4L Lincoln Nav engine here, is the ACTUAL Cobra R engine? If not, would authentic Cobra R parts actually fit on this Navigator engine?

Any feedback would be appreciated.

And now that i'm thinking about it...does this Navigator engine even have the same Engine Mounts to bolt up to the Mustang GT locations??

If i actually manage this swap this coming summer, anyone interested in my 4.6L SOHC GT Motor and 5-spd Trans?

BlackenedSVT · Dec 8, 2005

Also...is there a way to convert my T3650 6 bolt GT transmission to fit this new 5.4L Engine? I would rather NOT spend money on a new T56 transmisison (even though i would love one)...as i would like to keep this project as cheap as possible.

Can I just convert my trans to an 8 bolt main and be done with it? or no?

BlackenedSVT · Dec 10, 2005

info anyone?

BlackenedSVT · Dec 11, 2005

can anyone help me? what happened to this forum, what did everyone leave?

RedDaemon · Dec 11, 2005

ur posting at 1am on a monday, people have work in a few hours lol

i take that back ur origional post was from a while ago

person id pm would be i believe his name is billfisher...he just did a 5.4 3v conversion, im sure he can give you a lot of insight

BlackenedSVT · Dec 12, 2005

thanks ill try his pm. anyone else is free to help me out as well.

drew_shipley · Dec 12, 2005

Well first off you'd be buying a cast iron block 5.4 and the Cobra R was an Aluminum Block. Next, I don't know what intake manifolds you'd use. The Cobra R manifold was made to fit under a decently sized hood. This is going to be a lot of work, Good Luck

BlackenedSVT · Dec 12, 2005

Think i will need an upgraded radiator to help cool this monster motor?

How about computer changes..think i'll need to change harnesses or any crappy wiring projects like this?

squares98 · Dec 12, 2005

You'de be better of with a 9psi kb kit for your currrent engine, being exclusive does not have to mean being stupid,(pointless, unneccessary headaches, good luck selling it, etc)

billfisher · Dec 12, 2005

ok dude... it will fit. EVERYTHING to connect it will need to be fabricated. your computer will work.

the intake alone to fit will cost 3000-5000 dollars. forget the navigator intake, it is designed for torque. i passed up on one because it will cost at least $12000.00 in custom parts. bell housings are all the same.

that motor can kill a viper t-56. and real 31 spline rear ends. i am going to have to spend 10,000 dollars just on drvietrain. the brake system has to be made. mine clears it by 10mm. dohc is larger. if you have deep pockets and are experienced then do it. if you are not a master then no way. pay to have it done. good luck and enjoy it. if you start it, don't quit. keep researching and fabricating until you finish. i had to try 4 sets of headers and manifolds to just make my own in the end. but they gave me frame of reference for the ones i finally fabricated. just one example of hundreds i had to overcome. and i did it in 2 months. give yourself 1 year. i have done this kind of thing a million times.

YOU HAVE TO HAVE THE GREEN TO BE MEAN !!!!!

BlackenedSVT · Dec 13, 2005

Hey bill. i appreciate the input. I have found intakes on from Sullivan's for $629 though plus shipping. So i dont know where you got that quote of $5k-12,000 for an intake for this motor?

Anyway, yeah i am worried about the braking and the differential and rear end...as i will be keeping them stock until i can save up more money down the road.

My plans are to keep this as cheap as possible for as long as possible. Its not like i will be taking this to the track RIGHT after i install this motor...so there is no need to upgrade the brakes and rear because i know i wont really be doing any kind of racing until they are finally upgraded.

I realize a T56 would be ideal, but you think my stock Tremec T3650 is ok? I really dont want to change over trannys and driveshafts.

Bill, what about suspension? I have EIBACH Lowering springs currently with some Tokico adjustable struts...that enough to support this massive engine? Or should i upgrade to somethign else....again i dont want to if i dont have to.

ponysarepretty · Dec 13, 2005

How would it kill a Viper T-56? It makes nowhere near the torque that the Viper does.

hognutz · Dec 13, 2005

my .02 would be you stock rear and tranny will be okay if you know they are weak and don't run sticky tires and beat it too hard. make sure you get a rear cover that allows you to load the caps. don't launch on slicks. dr may even be too much.

3650 is rated at 360ftlbs of torqe. cobra t-56 is rated at 450lbs and viper t-56 is rated at 550lbs so you would be hard pressed to break the cobra t-56 unless you were launching on slicks then I am sure you could find a way.

I will thow in my .02 don't bother with this swap. there are hidden costs and headaches. $2500 for a forged shortblock. run stock heads, cams and boost it. for $7500 or so you could have a kb on top of it. you would only need the 1.7L for stock headss. you could have 500rwhp. nice thing about boost is if you fear breaking your drivetrain run less put down less power till you can affoard to upgrade the drive train.

rule of thumb if you can afford to break it you won't if you can't you will. Seems like the way my like goes anyway. right when money is tight that is when i drop a rear or a tranny.

billfisher · Dec 13, 2005

i talked to a racer that is driving a 8500 rpm 5.4 4v. he broke the hell out of a new t-56 and eaton posi in one run. as far a money. sullivan is for carbs. it is also tall as heck. 12000 dollars... here we go

hoses
radiator
harness changes
head work
forged bottom end(or blow up after 5500)
oil pan
exhaust headers
intake
intake elbow
TB
mass air sensor 90mm
injectors
fuel rails
fuel lines
hydraulic lines
PWM controller for proportional braking
remote solenoid operated braking.
fabricator to do brake system. - brake by wire
electrician to do COP conversion.
if not then bracket fab for ignition
adjustable regulator
injectors 24lb or larger
fuel pump in tank to keep up
cams (factory makes torque) you need hp
cowl hood.
labor for all the fabbing.
if you have to rebuild

the only person i know that has done it spent 12,000 for parts to turn it 7500 rpms.

if you stick to 5500 then less. i assumed you want hp. just because it has 4v doesn't mean it will make power with what is essentially 4.6 4v cams. 300 hp is not a lot for 5.4 4v. cams alone are $1000.00

sullivan is also just for HP. it won't make much at the bottom. even though these things make great torque they can't avoid throwing away 50 lb-ft with an intake like that at the bottom end.

i am probably going to but another motor to put forged stuff in. and head work.

1800.00 forged stuff
head work 2000.00
cams 900.00
hood 550.00 for you
motor 2900.00
your 3650 will die quickly.
your rear end will also.

i am going to take it easy until i replace them.

all that aside you can make 550 hp easy with the right parts.

billfisher · Dec 13, 2005

stock springs are enough. i dropped maybe 1/2"
the intake i was talking about is a low profile sheet metal that save torque. 3000 dollars

ponysarepretty · Dec 13, 2005

Hmmm... the people who supercharge their 8.3s and put down the best part of 700 lbft don't have problems with the tranny on the Viper... maybe he was just unlucky?

tomustang · Dec 13, 2005

i'd rather see a 4.6L cobra block with DOHC 5.4L heads w/ custom cams and sheet metal intake, but it's your preference

mity2 · Dec 13, 2005

i think Terminater engine is in the long run cheaper and easier. and its not hard to get 500hp out of them - certainly no harder then 5.4 nad intake to fit and tune and wireing and all other misc work you need to get 5.4 to fit

billfisher · Dec 14, 2005

if i had it to do over again...

terminator with cams or

just na 4.6 4v withthe works.

5.4 makes more power much easier. i started out with 300 hp. just like 4.6 4v, but i'm going to get more for the mod. the down side is the rpm's. piston velocities are crazy for 5.4. it is easier to spin a 4.6 higher to make up for it. the old elephant and mouse is the best example. the elephan twas the 392 hemi circa 1957 the mouse is the small block chevy. it kille the elephant with rpm's and gearing.

BlackenedSVT · Dec 14, 2005

Well originally i started the idea for this project because i have a personal preferance of N/A cars over power-added cars. And i felt the 5.4L DOHC was the way to go. Furthermore, i thought it would be a fun project to do.

Also, terminator motors (03-04 supercharfed) are about $12,000 right now, and a 5.4L swap would be well under that price, making close to the same power.

I realize i could easily do a nice KB supercharger for about $6,000 and have around 400 hp, but i just personally like the idea of N/A better. So i made this thread to get an idea of what the swap would entail, throw some ideas around, etc.

Bill, thanks for all the input. Hypothetically, if i did want to do your other option route (the terminator motor), got any idea where i could get one? How about a 4.6L 2001 or 99 cobra motor N/A??? I know karkraft has them, but i hear their motors aren't anything too hot...i just went to there site for the 5.4 motor because i can't find one anywhere else =/

5.4L DOHC Conversion Questions (need feedback)

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I like Pro3 and all I got was this crappy CT.

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