what is needed to swap to a 3 valve head?
I already have the 3 valve head, would I need different pistons? anything??

 

Depends on what all you can or are willing to modify.
Honestly,if you're asking these kinds of questions,this is NOT the swap for you.
JL

 

At the risk of being called a pessimist, it's a LOT of work. Either you need the entire 3-valver's electronics, including ABS/air-bag/PCM/dash-cluster and all the wiring, or you need to fabricate a throttle body setup to allow for a throttle cable, and do something about the variable intake plenum.

We can work on it with you, but it is a LOT of work. It's not just a bolt-on affair.

 

Krewat, I am ready for the challenge.

 

Good. Let's start with the idea of putting a 3-valve set of heads and intake on a 2-valve long-block, and using the original 2-valve PCM. Because without the 2-valve PCM you'd have to use the newer Torqshift tranny, which also requires all the electronics modifications I already mentioned.

You need to fabricate a throttle cable mount to the 3-valver's throttle body, and you need to figure out what to do with the variable plenum intake. Also, there was a guy on here, who later disappeared when he sorta got run off for trying to cook up a way to sell a conversion kit after sifting our collective brains for months while he built everything. He used a vacuum dashpot to modulate the variable plenum - and I'm not sure that's the best idea, but he seemed to think it worked.

That guy found out the cam position sensor throws a code when using the 3-valver cam position sensor with the 2-valver PCM. I THINK it might have had to do with the clearance between the sensor and the magnet on the cam gear, because he tried both the 3-valve sensor and the 2-valve sensor, and it still threw the code.

It ran, but always lit the check-engine light for the cam position sensor. Not sure if it was a "circuit" code, or just "not right" code

You'll also need the exhaust manifolds for the 3-valver.

 

doesnt the 3V pcm require the torqshift trans ???

and is it possible to use the 2V pcm on a 3V headed V10 ???

sounds like a nitemare to me..

 

Just offhand, what are you hoping for out of this modification? More power, what?

 

The guy who did it and got run off used the 2V pcm, a cobbled-together throttle body adapter to use the 2-valve throttle body on the 3-valve intake (I think, or maybe just cable setup on the 3-valve throttle body, don't remember) and found that the cam position sensor threw a code.

I was trying to work on that code with him when he got into the "kit" and got disgusted. Never figured that one out, but I suspect the clearance was too high between the cam magnet and the sensor, and the 3-valve PCM was more sensitive so it didn't care. Or, the cam magnet was in a slightly different place and the PCM was smart enough to deal with it. He said it ran good, had more power than the 2-valver. With a custom tune, who knows WHAT it could do. A small amount of machining to the face of the cam sensor bung, and again, who knows if that would have helped.

Going into it fresh, a person would have to compare the clearance between the sensor and the magnet on both the 2-valve and 3-valve, and see if the magnet was in the exact same spot, degree wise.

Interesting project.

If I had to do an engine rebuild on a 2-valve, I'd probably try it

 

my situation is I am doing a rebuild so I decided to put 3 valve heads. I don't know about engines but I have a friend who will do it for me. A few questions.

I know I need the 3 valve throttle body but what do you mean by throttle cable mount?

and will getting a custom intake manifold get rid of the variable plenum?

 

As a Ford dealer tech, I can tell you that your little "project" will NOT be a cheap proposition. To get a PROPERLY working V10 3-valve, you're going to need the PCM, transmission (Torqshift), all associated wiring, as well as the necessary plumbing needed to convert your existing return type fuel system to the returnless style that is used on the 3-valve engine.

Now, HOW MUCH of a challenge are you in for?

 

I want 3 valve power. I was doing a google search and there wasa thread were they talk about prototyping dohc cobra heads for the 6.8, is this even possible. Anyways on to the real subject here, I want to do it but I don't want to use the transmission I currently have, I have a c4 fully built.

 

The 3V engine throttle body is electronically controlled, there is no throttle cable. Either you need to mount and wire a pedal assembly from a 3V truck in your vehicle or you need a way to connect the throttle cable to the 3V throttle body.

Yes.

Anything is possible given enough time and money.

Then use a PCM from a manual transmission truck.

 

I'm assuming you already checked if you can get a C4 bellhousing to meet up to a Ford modular? (Actually, given the dragracing scene, I'm sure they already exist).

 

If power is what you are really after, it would be far cheaper and easier to just beef up your engine internals, and turbo or supercharge the thing while adding some other mods along the way. Trying to convert this over is going to be big $$$$$$$.

 

Pinky you make a good point, I was just thinking of getting a turbo for it but I want to know how much power can the block hold before it cracks. I dislike how people say 400-500 Hp I know it can handle more. I come from the mustang scene where 5.4 V8 make over 1000 Hp, and the v10 is the same with 2 extra cylinders. I am shooting for 800 Horsepower twin turbo. Its going to make crazy torque.

whats everyones take on 800Hp v10?