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Discussion Starter #1
Is it at all possible to use the heads and intake from a 98 - 99 DOHC Ford Mustang Cobra?

I am only asking cause considering that they are both OHC and use the 4.6L Modular v8 motor.

So anyone out there?

Is it something someone can do?

Thank you.
 

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Yes, they bolt on. However, they wont do much more than add weight using the SOHC bottom end.


This is one of those things where searching works wonders.
+1. The Cobra heads have a big combustion chamber (54cc). Throw in the dish pistons that you have in your block now and it will make for a low compression number.
 

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Discussion Starter #4
so what you are saying is that it would be a total waste of time unless i do a complete swap of the engine and the heads?


But would they just mate up to the current transmission that i have or would that also have to go as well?

Thank you.
 

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so what you are saying is that it would be a total waste of time unless i do a complete swap of the engine and the heads?


But would they just mate up to the current transmission that i have or would that also have to go as well?

Thank you.
you would be much better served getting pi heads if you just want to do heads. reason being pi heads are still bolt on. and they RAISE compression do to a much smaller combustion chamber which is what you want a tight combustion chamber with higher compression unless you plan on going forced induction. with the dohc heads the combustion chamber is much larger so you will have low compression meaning a lot less tq and hp.
 

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Pistons. Rods are meaningless for compression.
i thought dished pistons reduce compression? and if you have longer rods it can increase compression?
 

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i thought dished pistons reduce compression? and if you have longer rods it can increase compression?
The rods are all the same length in all 4.6's. The dish of the piston is what is different.

A 96-98 4.6L has 11cc dish pistons with a 46cc combustion chamber.

The 4V engines have a 3cc dish piston with a 54cc combustion chamber.

The 99+ 2V 4.6L have a 17cc dish piston with the 42cc PI heads and that is how the compression numbers stay about the same as a 96-98 4.6L

Clear as mud huh? LOL
 

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R8D-XXX;1230923 Clear as mud huh? LOL[/QUOTE said:
pretty much sums it up well lol
 

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I was looking to install 99+ 4v heads on a early mark 8 motor. Does anyone know if the compression will suffer also. Was thinking of a PI 2V swap but I like the 4V and how it looks with the big valve covers and hidden coils.
 

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I was looking to install 99+ 4v heads on a early mark 8 motor. Does anyone know if the compression will suffer also. Was thinking of a PI 2V swap but I like the 4V and how it looks with the big valve covers and hidden coils.
The compression will remain the same.
 

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Discussion Starter #13
Yes, they bolt on. However, they wont do much more than add weight using the SOHC bottom end.


This is one of those things where searching works wonders.

I was under the impression that DOHC stands for OVER-HEAD CAMSHAFT. Therefore would that mean its not a CAM IN BLOCK as it is in the older engines????


And once i replace the heads with the DOHC heads i should just get DISHED PISTONS and not change my rods at all right? Or did i misunderstand in some way?

Thank you.
 

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I was under the impression that DOHC stands for OVER-HEAD CAMSHAFT. Therefore would that mean its not a CAM IN BLOCK as it is in the older engines????


And once i replace the heads with the DOHC heads i should just get DISHED PISTONS and not change my rods at all right? Or did i misunderstand in some way?

Thank you.
dohc stands for dual over head cams meaning you have 32 valves 16 per head and 4 per valve. its the same style as the sohc just its double the cams and valves. you want flat top pistons as they wont cause a decrease in compression as dished pistons do. plus if your car isn't super/turboed theres no reason to have dished pistons.

the reason he says your adding weight is that you're gaining nothing matter of fact you're loosing. and that those heads are very heavy as they have twice the valves the cams and everything to go along with that.
 

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pi is the way to go cost wise.
 

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Discussion Starter #17
Therefore with the swap of the heads, i would be loosing performance, unless i have upgraded pistons, and/or supercharged my motor?

And as XR7-4.6 mentioned in the previous post, the amount of time and money would cost me as much as full DOHC motor?? Wow, i didn't know that it was THAT heavy :O

However if i swap the entire DOHC motor, is it just plug and play or would i also need the entire wiring harness of the full DOHC motor?

And from what year would it be the better DOHC motor swap?

I apologize if i am asking too many questions, however i have had my Thunderbird since May of 2006, and it doesn't even have 100k KM on the odometer. <fully verified>

If you would like to check it out here is the link to the page:
http://www.cardomain.com/ride/2814593

Enjoy the view.

And once again;
Thank you for answering my questions.
 

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well overall the best 4v you could get would be a cobra one with all forged internals and a supercharger sitting on top but thats gonna cost you one shiny penny. the most bag for the buck is a lincoln mark 8 lsc motor. then you take and put cobra heads on it and you're on you're way to making some very serious numbers. if you have the time place and money buy a mark 8 block get a supercharger kit for a 4.6 dohc cobra and some forged internals build that motor up and you'll get a mustang beater eater and killer.
 

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Therefore with the swap of the heads, i would be loosing performance, unless i have upgraded pistons, and/or supercharged my motor?

And as XR7-4.6 mentioned in the previous post, the amount of time and money would cost me as much as full DOHC motor?? Wow, i didn't know that it was THAT heavy :O

However if i swap the entire DOHC motor, is it just plug and play or would i also need the entire wiring harness of the full DOHC motor?

And from what year would it be the better DOHC motor swap?

I apologize if i am asking too many questions, however i have had my Thunderbird since May of 2006, and it doesn't even have 100k KM on the odometer. <fully verified>

If you would like to check it out here is the link to the page:
http://www.cardomain.com/ride/2814593

Enjoy the view.

And once again;
Thank you for answering my questions.
Best years for your car plug and play wise are going to be 97-98 DOHC.
Although it is possible to update the sensors and use a 93-96 as well.
 

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well overall the best 4v you could get would be a cobra one with all forged internals and a supercharger sitting on top but thats gonna cost you one shiny penny. the most bag for the buck is a lincoln mark 8 lsc motor. then you take and put cobra heads on it and you're on you're way to making some very serious numbers. but that engine weighs quite a bit so along with making good numbers you're adding a lot of weight. if you have the time place and money buy a mark 8 block get a supercharger kit for a 4.6 dohc cobra and some forged internals build that motor up and you'll get a mustang beater eater and killer.
I really wish you would stop posting crappy, incorrect info all over the place. A Mark VIII motor (which, by the way is no different from the LSC), is all aluminum. Therefore it does not weigh "quite a bit". Yes, the heads themselves are a little heavier with their sheer size and extra valvetrain components, but the overall weight is lower than an iron block with 32V heads. Why do you think the Teksid block is even sought out in the first place?
 
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