difference between mark 8 dohc and cobra dohc engines

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dahkid

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i havea stang and im lookin for a engine swap. so questioniswhat the difference between engines. could i use the cobra ecu? any response wouldbe helpful
 
have you considered a 5.4 out of a navigator? no replacement for displacement...
 
dahkid said:
i havea stang and im lookin for a engine swap. so questioniswhat the difference between engines. could i use the cobra ecu? any response wouldbe helpful
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ECU will be the biggest challenge. Otherwise, some differences are the cast vs forged crank, intake, exhaust cams, 8 bolt vs six bolt on the flywheel. There are a couple other small things. What year Stang are you contemplating doing this to?
 
Mark VIII has a different harness pinout, so you'll want the Cobra harness and ecu.

The engines are the same except for :

The intake manifolds are different.

Exhaust cam is retarded -5 degrees.

The pistons in the Mark are flat-top cast w/ 9.5:1 compression. 96-98 Cobra's are hypereutectic and yield a 9.85:1 compression.

The cobra has i-beam connecting rods.

The Mark has cast connecting rods.

The Cobra crankshaft is forged steel capable of 1500hp with proper prep work.

The Mark VIII is cast iron capable of up to 600hp.

I recommend you buy a coil-on-plug Mark from either a 97 or 98 model year. You should ditch the MArk intake and find a 97-98 Cobra intake manifold and composite IMRC's. What year is your Stang...
 
The pistons and rods are the same in the Mark VIII and Cobra. The compression is 9:85 for both.
 
95LSC32V said:
The pistons and rods are the same in the Mark VIII and Cobra. The compression is 9:85 for both.
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The pistons in the Mark are flat-top cast w/ 9.5:1 compression. 96-98 Cobra's are hypereutectic and yield a 9.85:1 compression.
 
Where did you get your info? That is the 1st time I have heard of that.
 
Tech book on moudular engines. There are more differences than you'd think...
 
If your thinking of doing a 4.6 SVT cobra mustang engine swap. You'll have to switch the tranny and get diff. computer harness to or some sort of harness and a couple of other things to. All of that plus the engine is very expensive about, $16,000. Ya I've already thoght about and said screw it b/c I'm a broke HS student:).
 
Hmmm... I am almost 100% sure the Mark VIII and Cobra have the same compression 9:85 thus leading me to believe they have the same pistons and rods. In the SHM book the only differences he talks about besides the crank and intake manifold are in the valvetrain, the 93-95 engines don't have the beehive springs.
 
Mark is 9.8
Cobra 9.85

The slight difference is in the pistons...
 
There is NO difference what so ever between the 96-98 Cobra pistons and the 1993-1998 Mark VIII pistons at all, they even have the same EXACT part # of F3LZ-6108-DA
 
Which explains the crappy ring lands on both, thus the lack of supercharger systems, or certainly, and the lower values in boost that are recommended.
 
I'm just about positive the 5.4 won't fit the Mustang chassis without some serious mods. It's taller and wider. But MM & FF put a Lightning engine in an old Fox body that worked. It looks like crap sticking out of the hood though.

Get a used engine from and 03/04 Cobra. It has completely forged internals including H beam rods. It also has a cast iron block for strength with the s/c. The compression is about 8.5 to one. There are a lot of those running 15 to 20 lbs of boost and living well if you don't take them on a long high speed run. Less than 15lbs seems to be just fine all day long. They are very, very easy to get 500 rwhp out of with a torque curve that is damn near flat.
 
2001LS8Sport said:
I'm just about positive the 5.4 won't fit the Mustang chassis without some serious mods. It's taller and wider. But MM & FF put a Lightning engine in an old Fox body that worked. It looks like crap sticking out of the hood though.

Get a used engine from and 03/04 Cobra. It has completely forged internals including H beam rods. It also has a cast iron block for strength with the s/c. The compression is about 8.5 to one. There are a lot of those running 15 to 20 lbs of boost and living well if you don't take them on a long high speed run. Less than 15lbs seems to be just fine all day long. They are very, very easy to get 500 rwhp out of with a torque curve that is damn near flat.
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Yea...you could go ALOT higher but, People are running in to problems with the pistons being too tight in the bores. During a WOT blast the pistons are heating up, expanding, and then galling up the cylinder walls.


Here.....http://forums.modulardepot.com/showthread.php?s=&threadid=53880




Mike



Edit..... this is on a STOCK cobra engine with nothing done to it cept' a bigger blower. Once new pistons are put in (or the bores opened up a few thou'), the problem is fixed.
 
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