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View Full Version : cubic inches on an 03 cobra?


v8musclecobra
10-13-2005, 08:55 PM
I always thought the cobra's engine was 390ci but my friend said it was only aroun 250. Is that true?

03slidewayzSVT
10-13-2005, 09:08 PM
4.6 liters = 281 cubic inches:thumbsup:

v8musclecobra
10-13-2005, 09:16 PM
damn i thought it was way bigger. thanks though.

v8musclecobra
10-13-2005, 09:19 PM
so if i tried to convert it to a 427, would i have to redo the whole engine, or could i use some of the stock parts? Im guessing do a whole new engine cause then i won't bother. Is there even a plus to doing it, like am i going to get a big hp/tourque difference or am i better sticking with the same size block?

Silver10th
10-13-2005, 09:44 PM
What Horse Power range are you looking for? For less money than a 427, that I don't think will fit, you can get 650hp out of that 4.6.
Where there is a will there is a way but I don't see the point in putting a 427 in a '03 Cobra.

v8musclecobra
10-13-2005, 10:47 PM
yea i was just wondering. Can't you bore out the stock block to 5.4 liters?

NO 5 OH
10-14-2005, 01:10 AM
What Horse Power range are you looking for? For less money than a 427, that I don't think will fit, you can get 650hp out of that 4.6.

A 4.6L DOHC engine complete with heads, etc. is exactly four inches wider than a 429/460 big block from the muscle car era. For such small displacement that the 4.6L is... it's amazing as to how big the motor actually is. However it is true that you can make an easy 600 plus to the tires with an 03/04 Cobra motor... I know this for a fact ;);)


Shannon

ausie
10-14-2005, 07:13 AM
It may be possible to bore the 4.6 out to 5.0L but not to 5.4L unless you stroke it. If you want larger displacement, buy an 07 Shelby 500gt.

The issues I see with going backwards (427) may be engine mounts, transmission, fuel system, etc..... I am sure it can be done but would it be worth it?

Riversnake
10-14-2005, 08:39 AM
You can always do like I do; when some of those "know-it-all-smart-a55es" wants to know "Man, what size engine is THAT?" I have started grinning and telling them "Its a 427!" :D

blk04cobra1
10-14-2005, 08:54 AM
Im putting a 302Stroker in mine with a Dart wet sleeve block...hopefully this winter, but we'll see how the $$$ flows until then...gotta have a block to support the twin 67's :eek:

v8musclecobra
10-14-2005, 07:06 PM
goo luck sounds like its gonna fly. Thats wierd though that the cobra engine is actually bigger then a 427...ford shoulda made the displacement on the cobra bigger. Id like to get the 07 gt500 but i don't have that much money lol.

v8musclecobra
10-14-2005, 08:59 PM
i was looking at the modular performance 302 stroker kit and was wondering if that replaces everything in the existing engine? Do any of the stock parts stay the same? Can you use the stock eaton supercharger on it?

InfamousSVT
10-18-2005, 12:57 AM
VT engines have a few options out there for an upgrade for the Cobra motors.

I've seen a few guys go up to a 302 and others a 324


Although you can get a mad amount of horsepower out of these engines straight from the factory with a few bolt-on's, it really depends on the tune as to how long it'll last

blk04cobra1
10-18-2005, 09:43 AM
The modular and VT motors replaces the main components of the motors (pistons, heads, rods, etc) and you can use the stock charger, but most dont b/c the stock motor can handle all the power from the stock charger

v8musclecobra
10-18-2005, 09:35 PM
well, i was going to go twin turbo but decided to do kenne bell with nitrous and suspension upgrades. This way i have an all around better car for less then twin turbo. Im kind of a low end guy anyway.

Dave B.
10-18-2005, 11:45 PM
I was told the 4.6 03-04 cobras are a 289 cubic inch

Guess im wrong about this right???

cobrabitn
10-19-2005, 12:01 AM
They are 280/281 cubic inches whichever you want to round it off to? 289 is incorrect.

Dave B.
10-19-2005, 12:05 AM
I stand corrected
you know thats a lot of horse power they get out of that little engine, years ago I would have never thought it possible,

kilroy
10-20-2005, 12:15 AM
I recall the 4.6 displacement as being 280.8 cid. Rounded up 281. Steve Saleen's graphics read S281:thumbsup:

With the huffer atop the 03-04's it certainly acts much bigger than it is :cool:

kilroy
10-20-2005, 12:21 AM
I was told the 4.6 03-04 cobras are a 289 cubic inch

Guess im wrong about this right???Dave, a few years ago Kenny Brown was selling 289cid motors/turn-key cars if memory serves me right. They were bored/stroked 281s I guess to pay homage to our 289cid heritage. I bought the t-shirt :D

secondchance
10-21-2005, 10:33 PM
Your question got me to thinking about the actual displacement. Using 90.2cm bore and 9.0cm stroke gives 4600.82 CC that converts to 280.76 CID. The stock Eaton at 8psig max boost gives 280.76 * 14.7/8 = 515.9CID so the raw air volume is actually larger than the 427. The higher RPM range of the DOHC motor provides higher throughput than the NA 427.

secondchance
10-22-2005, 12:42 AM
Your question got me to thinking about the actual displacement. Using 90.2cm bore and 9.0cm stroke gives 4600.82 CC that converts to 280.76 CID. The stock Eaton at 8psig max boost gives 280.76 * 14.7/8 = 515.9CID so the raw air volume is actually larger than the 427. The higher RPM range of the DOHC motor provides higher throughput than the NA 427.

Duh

280.76 * (1+8/14.7) = 433.55CID equivalent volume

Sorry :stupid:

v8musclecobra
10-22-2005, 01:13 AM
o ok so basically a charger will make up for the ci inches then. Makes me feel a little better. I also saw a guy with 1200 procharged cobra running low 8's i think on stock block. So i guess it can take a lot. It was in 5.0 mustangs and superfords mag with the orange cobra on the front if your interested. I could gett he volume and issue if you want.