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2003 cobra 4.6L in a 240z?


dippowit-z-

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Guest iskone

HIt up the search. That's the first place to start.

 

You'll find that the 4.6 is very wide on the top and could possibly be shoe horned in. Someone here has taken measurments but AFAIK no one has done the swap.

 

Isk

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The engine will fit between the towers (per a string quite a while back), but the issue of the steering arm/exhaust manifold clearance (which can be addressed) was not determined. I'd like to see if this will work as we've had several "nibbles" but no one as yet to take the bait and actually do it.

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I am a former REBELLO customer. Although very pleased in the past, I think that I may get alot more for 7000.00$ than just a 3.2L six cylinder. I need advise or ideas about different options. I am an accomplished metal fabricator but I do not want to alter the unibody of my car. OK, go...

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they're HUGE!!!!!!!!!! (talking about the DOHC) Have you seen one next to a 5.0? They're almost twice as wide, no joke. The heads are about as big of heads as have come on anything and the 4.6 block is wider to begin with.

 

They're heavier too. WAY heavier.

 

Even if you fit one (i'm sure you could) it would have a horrible weight distro compared to a 5.0. Why would you want to do it? I'm not saying you should. I love seeing any type of conversion. BUT, if you're looking for pure performance I wouldn't go with it. Newer cars are getting heavier and heavier, and the motors are sucking up to the challenge. The newer motors are heavier, and beefier, but if you can get 600+ solid HP out of a 5.0, why go with something newer? Sure, a 03 cobra can run 9's on a stock bottom end, but that doesn't mean it's a great match for a Z.

 

Parts are more expensive too.

 

Like i said though. If you want to do it, go for it. You'll get support from people here i'm sure (as much as we can offer over that net that is) but I just don't recomend the swap for the performance oriented.

 

Gratefully,

Gollum

 

PS I LOVE the 03 cobra and it's nice to see the mustang back competing with the stock stangs of the 60's. And the new gt500 should SO have a SVT badge.... GRRRR

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As I said, I'd like to see someone go where no one has gone before, but the 5.0 is about as efficient (in terms of weight, size, and power) as you can get. The 351W is really the same motor except a higher deck height and width (what...1 1/2" at most?). I like the 4.6L on paper, but in the real world, the older 5.0 or even an LS1 is where I'd focus my attention.

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my dad has a 99 cobra and its basically the same engine as the 03 but not supercharged and i know that it has an all aluminum block and aluminum heads so it has to be pretty damn light. If you want my opinion use the cobra engine there sweet engines and ive never heard of anyone using one before. I know if i could ever get my hands on one i would use it so go for it

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  • 2 months later...

the 03-04 cobra blocks are made from cast iron, so it is not all aluminum. those engine weigh 600 pounds(cant remember where i read that, maybe MMFF), with the block weighing in at 190 pounds alone( i have one sittin in my bedroom). They have cross drilled 4 bolt mains, and the DOHC engine are much better than the SOHC engines. The DOHC engines have 32 valves, 4 per cylinder, and the SOHC engines have 16 valves, 2 per cylinder.

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Guest 73Turbo240z

the cobra engine is also prone to detonation on account of heat soak of that cast iron block... which would be compounded by the Z's engine bay not being very proficient at moving air through it... creating a hot pocket encouraging heating.

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LS1, LS6. Lighter, more displacement, you can get them all day on Ebay with a 6 speed T56 for under 5k and that includes the computer a lot of the time. If I had to stuff another engine in my 510 it would be this one. From what I've read re: engine weights recently it's lighter than the 7m-gte I have in there now.

 

Anthony

http://www.cardomain.com/ride/674663

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like ive said in every other ford engine post. Central coast mustang block for $1900 it is new and makes 300hp, thats not enough then $2300 for 340 and $3000 for 370. More then that hop onto the 351 design it has a beefier bottom end (and weighs about 80lbs more) then the 302's and will make plenty of power. But you have to ask yourself how much you want to make, 500 is about the max on the 302 before you need to do some super beefing, the 351 takes some more. Also, if you have a 7k budget, get a world products block or aftermarket block (from a good company) that is designed to take the beating. The world products one for instance features 4 bolt mains as well as other structural goodies. I would try to stick to the 302 though seeing as it has a good weight and decent power output plus, distributor is on the front (on almost if not all fords) so it can be mounted all the way back, better weight distribution.

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  • 1 year later...
Guest bojo68

Well, a 4.6 dohc is what's going in mine. If ya look around here you'll find where somebody with the top hacked off a z had one in theirs, showed a few pics but never followed up on what he said he would with the rest of the pics. There were all kinds of comments that it wouldn't fit, along with erroneous measurements, then came the pics of one in place. One guy commented how tight it was, to him I say go pop the hood on a BMW 750il v12, or a jag xj12 for that matter. I think they're EASIER to work on than the factory 6, I can get at the exhaust manifold bolts on a 4.6 dohc in a z and the plugs come out from the top, real easy. More importantly, they seldom need to ever come apart.(they don't loose head gaskets or blocks like 5.0 and l28. To make any real power the biggest problem the way I see it is going to be the tranny, the manuals capable of living are more expensive than this entire project, so I guess I'll either have to see how long a built 4r70w will live, if that fails I'll probably have to choke down buying an adapter to a 4l80e, which are spendy, probably more than another build on a 4r70w. Anybody ever put a viper differential in a z? Any bright ideas on what it will take to make the rear end hook and track straight?(I'm thinking changing the geometry on the mounts for the a arm.)

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