Navi ports are different. Not interchangeable. In reality Ford currently has 3 different 4.6/5.4 4v heads. Cobra, Navigator, and Cobra-R all are different. All will bolt on to either a 4.6 or 5.4 block, but that is where it stops.

 

I ordered a DSS 5.0 Bullet short block from them back in like '95 or '96 or so for my Mustang. Had some problems with some of the parts not being torqued correctly. Wound up selling the block before I used it. I've heard other stories about them also. Maybe they've changed by now, I don't know.

 

SHM,wants 15k for a similar 4 valve that is built,but for around 7.5-8k,this motor could have all new internals and be studded,ported,balanced,and have a new intake....do the math and you will realize why i posted this in the first place.

Most,that are willing to go through the hassle of swapping in this motor,would go all out,so whether you by it from Karkraft or DSS is kind of a moot point IMHO.

The differences in 4 valve heads has been discussed numerous times,and as recently as two weeks ago on this board.

 

Moot: arguable.

 

I actually purchased a used Navi engine for $750. I then ordered the rods and pistons I wanted and then sent everything to the machine shop. I am still mulling over what to do with the heads. I have spoken at length with Sean Hyland concerning this project, and Sean is supposed to be offering the lower intake plate for the switch to a 32 valve. I don’t think he (Sean) has worked out all the kinks in the fuel management department. The last time we spoke, he was using a stand-alone fuel management system. Unfortunately, I have way to much time and money tied up to quit at this point.

 

Actually, I thought it meant they rebuilt it to work with cobra heads.

 

I searched around for a thread on the differences between the Cobra heads and the Navi heads. I was not able to find it. I have the technical differences between the 2000 Cobra R heads and the Navi heads, however I will not picking up any Cobra R heads anytime soon. Does anyone have or can point me to the thread that details the differences between the 4 valve heads?

Thanks

 

Thought four valve 5.4 wouldn't give us the torque we need to get our heavy L's moving.

Mark

 

Who the hell told you that?

 

Just quoting from memory, but I had read that the four valve produces HP & Torque at highter rpms and money would be better spent on our two valve motors. Not my research or opinion, but post seemed logical.

Mark

 

That is true in simple moduler basics the 4 valve will riase the powerband and have less torque to horspower ratio. but with some kind of power adder you can narrow that margin.

 

Aryton,
If you have the Navi heads now don't switch to the Cobra heads. The Navi's have larger intake ports. Much better choice for a Lightning application. With the Eaton on it torque will not be a problem. Tranny will be the next problem.

 

Aryton, the posts on the 4 valve head differences were within other threads.
Sal was the last person that i saw, explaining it to another member.

my engine builder got around 80 hp out of a set of n/a cobra heads,and that is a lot of power in anyones book.

Aryton,if your interested,shoot me an e mail and you can contact him about porting your navi heads.

And don't go through the hassle of buying a new intake,and then slap on the inefficiant m112.....think bigger,more efficient aftermarket blower IMHO.

 

Just think what a built 5.4L block with a newly cast aluminum intake and a 201ci blower and custom cast intake plenum from Works will do for you along with a set of Navi ported heads.

Me thinks it will give some major HP/Torque............ especially with the custom cams.

Available in 2003.

Tim
REM