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03/04 Eaton Conversion (96-98, 99+, Mach-1, 99+Cobra)


Well-Known Member
Staff member
Denver DOHC Cobra - Request this be a sticky, a lot of 96-98 Cobra owners, 99+ Cobra and Mach-1owners wonder what it takes to bolt on an Eaton M112.

There are many of these units available for as little as $400 due to the KB and Whipple upgrades to 03 Cobras. At first glance it seems like a low cost way to boost your N/A Cobra or Mach-1, when in reality its very expensive to get all the parts together ($7000+ and more like 10,000+ if you do it right and forge your bottom end).

Not to put down those with the ability to fab things up, but in reality picking up a $400 Eaton and fabbing up some sort of drive system is really not doable, you are talking about 6500+ RPM and the system needs to be very well engineered.

That leaves things to trusting Ford and just converting to the 03 format and just bolting everything on (and it's just that simple, it's pure bolt-on for 99.9%of this upgrade). Just educate yourself of how many parts it takes to complete this bolt on, and how little of those parts are included in your typical E-Bay auction.

You can also purchase an 03 motor, many can be had for $7500 to $9500 and in most cases include a T-56. In many cases you can slide in this new forged powertrain for less than the cost of converting your existing non-forged block to the 03 format.

I found a unique auction (and it was not your typical Eaton removal for upgrade), someone had actually trashed an 03 motor so they removed 100% of the parts (except the timing cover & trashed heads) from that motor and I won the auction for $2500. I had every nut, bolt, clamp, coolant line, vacume line, and upper/lower engine harness wires needed to convert to the 03 format. All I had to buy was an 03 timing cover, 03 heads, and an 03 oil cooler. Even with all those parts, in the end my All Alloy Terminator conversion ran $14,000. I did add every upgrade I could but even if I went pure budget this conversion would still have cost about $8000.

Mach-1 and 99+ conversions are least costly because you already have C heads and with the Mach-1 you alreay have 03 Cobra heads. Still it's a costly venture. In these cases you need the 03 timing cover and all accessories, and all the top of the motor parts, and all the intercooler parts, and it can be done with the motor in the car. You end up with a non-forged 03 motor that should stay at around 6 to 8 psi (maybe an 80HP upgrade that costs you $5000+).

Here is a general list of what you need to convert your 96-98 short block to the 03 format (99+ Cobra and Mach-1 folks just delete the heads). I'm flowing visually as a molecule of air getting sucked in through the air filter and flowing through the motor:


03/04 Cobra Plastic intake parts (or aftermarket 03 CAI).

03/04 Cobra 90mm MAF (or LMAF, or SCT Big Air or other aftermarket MAF).

03/04 Cobra TB (or Acufab or other aftermarket TB).

03/04 Cobra inlet plenum (comes with Acufab if you go that route).

03/04 Cobra Eaton M112 (get a ported one if you can).

03/04 Cobra Intercooler w/metal water line fittings, o-rings & attachment bolts. Also for this system: intercooler pump, bumper mounted heat-exchanger, plastic resivour, and all connecting lines.

03/04 Cobra lower intake manifold, metal gasket to Eaton & attachment bolts, gaskets to heads and attachment bolts.

03/04 39lb injectors, or 42lb Bosh injectors (42lb Bosh will mate to your existing 96-98 harness, 39lb will mate to your 99+ harness)

03/04 fuel rail (96-98 owners need to spend more money in this area, you actually need to convert the 03 lower manifold to work with a return style fuel system. You need aftermarket fuel rails, fuel pressure regulator, and all the lines and fittings to connect it all up, runs about $700 if you include the intank 255LPH pump).

03/04 Cobra Heads (or any 99+ "C" heads will also mate to the 03 lower manifold). You will also need new head gaskets (I suggest MLS) and new head bolts as you cant reuse Ford TTY bolts. I suggest an ARP stud upgrade.

03/04 Cobra exhaust manifolds required if changing to 03 heads (they have larger more squared off exhaust ports).


03/04 Cobra timing cover (costs about $465 through Ford, comes with new front seal and idler pully on drivers bank). If using an aluminum block one bolt hole does not line up and all you do is leave out the bolt and RTV in that area.

03/04 Cobra harmonic balancer (has threads to accept the 8-rib 03 Cobra supercharger drive pully)

03/04 Cobra 8-rib supercharger drive pully & mount support & bolts.

03/04 Cobra Alternator (has 8-rib pully), 2 mounting supports & bolts. You also need the 03/04 alternator 3 wire electrical connector (just splice it into your harness).

03/04 Cobra upper pully assembly, has idlers and tensioner that guide/route the 8-rib supercharger belt).

03/04 Cobra 8 rib supercharger belt (or aftermarket belt sized to work with your combo if you have elected to change your S/C pully to a smaller size like 3.1, 2.8, or 2.7)

03/04 Oil cooler (it will mate to your existing oil cooler flange).

03/04 coolant crossover tubes (you will need to add 1 extra water temp bung for your 96-98 computer, and another bung if you want to add a water temp gauge).

03/04 coolant lines and thermostat housing assembly.

You can reuse your A/C compressor, P/S pump, and water pump as these 6-rib units will work with the 03 timing cover system. You will have to bend and tweak your P/S lines to get it to work.

Tuning: you need a tuning system for your 96-98 or 99+ computer: I suggest SCT racer tuning software @ $850. Or get a mail order chip, but be prepared to pay $1000+ to have someone dyno and re-burn your chip to tune & tweak your motor to perfection. NOTE: Full conversion to the 03 computer requires use of an 03 instrument cluster (has digital odometer) which means changing the entire dash harness.

Gauges: you need Boost, Fuel Pressure, and Wideband 02.

Ignition: you will need a Boost-a-Spark or MSD system.

Fuel: If gong with a 2.8 pulley you will be at 450ish HP and you will need to look at upgrading your fuel pump. For 96-98 return style systems a $90 Walbro 255LPH pump is the best choice.

Bottom End: the stock M112 Eaton with 3.5 pulley will get you around 8 to 9psi. If you stay with your stock non-forged bottom end you MAY be OK. I firmly suggest if you are spending $5000 on these parts to go ahead and forge your bottom end with Manley H-Beams, ARP 2000 rod bolts, and JE or Diamond Racing forged pistons. Then you can go with a 2.8 S/C pully and get to 14psi @ 465+ RWHP.

In closing:

Buy SHM's how to build Max Perfomance 4.6 motors, it's really a good resource for 4.6 101 questions and understanding many details about Cobra motors.

Look at the exploded Terminator motor pic in my website (E-Mail me for a copy you can zoom in on), study and learn about all the parts I have been talking about.

Go to my MSN site to see how one can take a 96-98 Teksid block and make an all alloy forged Terminator, adding 200+ HP to your Cobra.

PM Joe D for details and a great example of how to install a 03 Cobra motor/T-56 tranny combo (now upgraded to a Whipple) into your SN-95.

If after all this you are loaded with extra cash and completely Terminator crazy, Joe and I will spend all the time you need to help you part with your cash and get your project up and screaming...
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Well-Known Member
Staff member
99riocobra - provided this info

03-04 Eaton blower on 99&01

Originally Posted by 99riocobra
i will first start off by saying please use that brilliant thing they came up with a while back called the "search" function. please! with that said, here's a list with some part numbers, and then the list i made on my own that's more "generic" but sometimes easier to interpret....

1.) 2R3Z-6312-BAA Crank pulley /Harmonic Balancer
2.) 2R3Z-6C254-BC Supercharger Crank drive pulley
3.) 2R3Z-8678-BA Pulley w/mount Replaces stk alt. Pulley
4.) 2R3Z-8B603-BB Pulley bridge assembly for S.C.
5.) 1L2Z-8678-AB Idler pulley,timing cover LH side
6.) 2R3Z-6D080-BC Timing cover
7.) 2R3Z-6020-AA Timing cover gasket LH side
8.) 2R3Z-6020-BA Timing cover gasket middle
9.) 2R3Z-6020-CA Timing cover gasket RH side
10.) 2R3Z-10A313-AB Upper alternator bracket
11.) 2R3Z-10153-BA Lower alternator bracket
12.) 1U2Z-14S411-TA Electrical connector (alt. to harmness )
13.) 2R3Z-6B209-AA Tensioner on timing cover
14.) 2R3Z-8260-AB Radiator hose
15.) 2R3Z-8A593-AB Radiator hose
16.) 2R3Z-8K576-AA Radiator hose
17.) 2R3Z-8286-AB Water cross over pipe
18.) F8ZZ-6881-AA Cobra oil cooler adapter
Note: Use your stock gasket from your adapter or a leak will occur
with a Cobra gasket!
19.) 2R3Z-6A642-AA Cobra Oil cooler
20. 2R3Z-9002-AA Cobra fuel tank
21.) 2R3Z-9H307-AB Cobra fuel pump
22.) 2R3Z-6F066-AA Eaton supercharger & inlet / T.B.
23.) 2R3Z-9424-BB Lower intake
24.) 2R3Z-6K775-BA Garrett factory intercooler
25.) 2R3Z-9H486-?? Intercooler to S.C. gasket
26.) 2R3Z-9A758-AA Cobra throttle cable
27.) 3U2Z-14S411-JUA IAT sensor connector
28.) 2R3Z-9H308A-?? Intercooler pipe to heat Exchanger
29.) 2R3Z-6K683A-?? “……………………………………..”
30.) 2R3Z-6K683B-?? “…………………………………….”
31.) 2R3Z-6K683C-?? “…………………………………….”
32.) 2R3Z-6K683D-?? “…………………………………….”
33.) 2R3Z-6K683E-?? “…………………………………….”
34.) 2R3Z-6K683F-?? “…………………………………….”
35.) 2R3Z-6K683G-?? “…………………………………….”
36.) 2R3Z-8501-AA Ford / Bosche water pump for intercooler
37.) 2R3Z-9L440-?? Factory heat exchanger
38.) 2R3Z-8A193-?? Heat exchanger mounting bracket
39.) 2R3Z-6C693-?? 2each bracket clamps
40.) 2R3Z-9H308C --?? Lower manifold to intercooler water adapter
41.) 2R3Z-6F089-?? EGR Valve
42.) 2R3Z- -?? EGR Tube to exhaust manifold
43.) 2R3Z- 8N500-?? Water pump intercooler bracket

*** #29-35 are intercooler lines

My List:

1) all intercooler lines and elbows
2) intercooler fluid reservoir
3) heat exchanger and mounting brackets
4) intercooler
5) intercooler pump and mounting bracket
6) intercooler cap(mounts to front of lower intake and has 1 in and 1 out intercooler line)
7) intercooler pump wire pigtail
8) timing cover
9) every single pulley except AC and water pump
10) supercharger pulley bridge that a few idlers mount to
11) both belts
12) lower intake
13) IAC valve(that thing that sits on top of the plenum/elbow)
14) supercharger and plenum
15) alternator and both mounting brackets
16) alternator wire pigtail
17) throttle and cruise cables
18) throttle/cruise cable bracket that mounts on the blower
19) the whole vacuum assembly and the stuff it all plugs into on the driver side of the blower
20) main feed line coming out of PS reservoir(the bigger one going to the pump)
21) return PS line(the other smaller one out of the reservoir) as well as the sections that "T" to right next to the radiator and to the booster
22) pcv valve and hose
23) EGR valve
24) EGR tube
25) oil cooler
26) all of the soft radiator hoses:
a) upper hose going from the crossover tube to the radiator
b) the big long one going from the middle of the crossover directly down and goes into the thermostat
c) lower hose going from lower radiator to t-stat(about 10" long)
d) hose going from oil cooler to t-stat(about 10" long also)
e) smaller diameter hose going from bottom of coolant resevoir to t-stat
----> the last hose (e) may not be needed to swap, but i did anyway
27) coolant crossover tube(hard U-shaped tube going from head to head)
28) fuel rails(i'm not sure if the pressure sensor on the driver side rail is the same, but we swapped that too)
29) boost bypass valve actuator(circular thing with on the rear driver side of the blower)
30) gaskets:
a) intercooler cap(mounts on front of lower intake)
b) plenum to blower(if you get a supercharger with the plenum on already, then you don't need this)
c) throttle body to plenum
d) IAC valve to plenum
e) EGR valve to back of blower
f) timing cover(3 parts to this gasket, and they are all sold separately)
g) supercharger to lower intake(this one can be reused if you can het the original from the guy with the 03)
h) you can also use your original lower intake to head gaskets. you just have to cut off two small tabs(one on each one). you'll see when you try to line them up with the 03/04 lower intake. no big deal at all, takes 3 seconds.
-----> you'll also need to do something for fuel. stock 03/04 injectors are fine. you can run a BAP on your stock pump, or swap to the 03/04 tank and dual pump setup too...
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