5.4l Dohc Swap

TeamCaffeineGT said:

Hey all,
Thought I would write a bit about a project that I have somewhat completed recently(are they ever really complete?). Apologies for the novel!

After driving home for lunch one day, I parked my 01' GT in the driveway. I went in, had a sandwich and came back out to go back to work. My beloved Mustang of 12 years decided at that time that sputtering, knocking and finally dying was a better alternative than driving back to work. I was late for work, so I jumped in the F250 and left my pony there...broken.

Fearing the worst, I started talking a bit with my buddy at work about rebuild options and possible engine swaps. He owns an 82 LX 4 cyl that he did a 302 conversion on. No replacement for displacement was the motto apparently and he convinced me to take on a 5.4L DOHC swap into my GT (a little more discussion and he might have convinced me to try a 6.8L V10 swap!). I did extensive research on the swap, including reading through several forums from years ago that went into the pitfalls of such a swap. Not one to turn down a challenge, I forged ahead full steam. After some extensive begging and pleading with the wife, I was allowed to sink a bit of our hard earned money into the project. I set a budget of roughly $1500 and went to work sourcing the engine.

As you well know there are only a handful of vehicles that Ford has put this engine in. The 2000 Cobra R, Ford GT, 2007-2012 GT500s, a few Australian models and the 1999-2004 Lincoln Navigator. With such a meager budget I'm sure you can guess my candidate! I found a 1999 Navigator that had just come into a salvage yard within 40 miles of the house. The Lincoln was running strong, but needed a new transmission. The asking price was $1200 for the complete engine which included shipping to my door. I took the plunge. A few days later on a rainy day in April, a flat bed wrecker backed into my driveway and I had my engine.

I thoroughly cleaned the engine and inspected it for wear. Everything looked really good, but I decided to put new rod bearings in it just to be safe. I pulled the 4.6L and began the process of interchanging everything that I would need from it to the 5.4. I swapped the motor mounts, oil pan and pick up, flywheel (sourced from an 03 Cobra), trans plate, and some of the accessory drive pulleys as I decided to go with the 6 rib as opposed to the 8 rib.

The next decision that I had to make was that of the intake. I could try and find one of the Boss 260/290 intakes out there and pay over $1000, maybe I could find the unicorn Cobra R unit, or perhaps a supercharged setup from a Ford GT or GT500, I could even run a sheet metal unit!

There was/is a great article out there on one of the other forums that talked about using the 2012 Coyote intake as the ports match almost exactly. I was skeptical, but also adventurous. I went out on eBay and found the intake for 60 bucks. Turns out a lot of the coyote guys like to run the Boss 302 intake on their 5.0s! I could have gone that route as well, but again with budget in mind I decided $60 versus $600 was the way to go. The next step was drilling and tapping the cylinder heads...I don't recommend this as it is quite nerve racking. I decided to fabricate some 1/4" hold down plates for the middle sections of the intake where the heads have no material. Other forums have pictures where member's have welded aluminum plates in the void on the cylinder head. In retrospect, I might have spared myself the hassle and went with MMR adapters. These units are pretty slick, but also pricey. At the end of the day I got the job done with hand tools, swearing and maybe a tear or two.

Wire harness modification was next. I retained the factory 4.6L harness and ECM. This required that I slice the coil wires and plugs out from the injector harness sections. I also had to extend these wires to compensate for the length to run the plugs to the coils in the middle of the cylinder heads. I soldered in and additional 6" on each bank and to be honest I could have used a little more to make things fit even better. I also extended the wires for the TPS, coolant temp sensor, IAC valve and soldered in a connector for the 95-98 MAFs.

I used 24lb injectors from a 96-98 Cobra and a MAF from the same. These were held down to the coyote manifold with custom fabricated fuel rail hardware and the fuel rails from the 01 GT. In order to clearance the heads, I had to use fuel injector hat spacers on the base of the injectors to raise them up high enough for the injector connectors. I believe they were 1/2 spacers.

With the fuel system sorted out, I turned to fabrication on the air intake system. I decided for now to run the throttle body from the 01 GT on the coyote intake. This required that I fabricate an adapter plate for the throttle body to intake. I used 1" 6061 aluminum plate for the adapter. I used Lokar for a longer throttle cable. I pieced together the air intake pieces from a CAI that I had previously and ordered a 90 degree silicon boot to mate the system to the throttle body. The IAC was mounted to the intake with a fabricated bracket. I used threaded hose fittings and a hose to plumb the IAC to the intake.

The coolant system was another item that I saved a ton of money on with a little ingenuity. I fabricated and "pressed" into the cylinder heads some barbed pipe fittings that I sourced from the local hardware store. I then welded some hold downs to the fittings and bolted them to the block. I ran a couple 90 degree hoses up to a T that joined the two sides together. Many trips to the parts store and I finally found the upper radiator hoses needed to circumvent the air intake system. I used an inline coolant temp sensor adapter as well as a Meizere inline thermostat housing (after a few coolant issues I opted not to run a thermostat). MMR also has a kit for the coolant system that utilizes AN style fittings.

The accessory drive was last on my list. Everything was the same as stock with the exception being the alternator. For this I fabricated a reverse mount bracket system and mounted the alternator right behind the coolant reservoir tank. Again, this could have been done differently with a bit more money, but I was determined to save as much as I could. The best method for this that I have seen is to use the Cobra lower coolant casting and a kit from MMR to mount a powerstroke alternator below the power steering pump. You could also retain the stock mounting location by utilizing a sheet metal intake with the navigator lower, or one of the Boss 260/290/302 intakes.

For the exhaust you can use the passenger side Navigator manifold, however to clear the steering linkage you must use a 99-01 Cobra manifold on the driver's side. I removed all EGR components on this swap as the intake has no accommodation for them whatsoever. I had a muffler shop fabricate the down pipes that feed Magnaflow Hi-Flow Cats, an H-Pipe, Summit Racing Street/Strip Mufflers and Pace Setter resonator tips. All O2 sensor locations remained the same.

Tuning was accomplished using a Delta Force Sniper Special Forces Gas unit.

The car is daily driven and runs very good. I don't have any dyno numbers as there isn't a shop around here that offers the service, but I can tell you that the car has more power and a lot more torque than the 4.6L. I am currently running 3.55 gears and have a set of 4.10s on the shelf, however for the sake of the tires I am not sure that I will swap them in.

I referenced several websites and forums during this swap. One great quick reference site is http://www.sullivanperformance.com/yvs450/tech/tech1.htm.

Many have reservations about this swap, but I am very happy with it. All said and done I had a great time with the swap and am proud of the work that I accomplished. I will say though....$1500 bucks because of a $150 fuel pump failure didn't make the misses too happy.

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