Navi Head Install

[nik46notch]

I just purchased a set of Navi heads for my 03 cobra shortblock. I was just wondering if anyone has done this and if there were any snags to run into..let me know..thanx

 

[droptop351]

you have to modify the lower intake to fit the ports on the naviagator head is the only thing im aware of.

 

[SlowSVT]

The navi heads don't flow like the terminator heads. I think the exhaust port shape is different to which will limit your exhaust manifold options. Not sure if the water jacket design is adequate for all the heat your gunna make. Personally I would spring got the 05 replacement cobra heads is you got the dough. They come complete with cams and are a drop in repalcement.

.......something to consider

Your car should make for a real sleeper. Good luck

 

[HISSMAN]

Jan. 05 heads > 03/04 heads > Navi heads.

 

[SlowSVT]

Jan. 05 heads > 03/04 heads > Navi heads.

More like: Jan 05 heads > late 04 heads (9 spark plug threads) > early 04/03 heads (4 spark plug threads) > navi heads

i'm just being picky

:burnout:

 

[nik46notch]

the navi head exhaust port is identical to the 03 cobra head, and the intake port is larger than the 03 heads. cc is .5 point off from the cobra heads and lobe lift on the navi cams are larger. same valves and components per ford and fox lake. i dont care if i lose a few horse i was just wondering if it all can work..thanx for the input guys

 

[sya5]

ill give u $20 for those navi heads

 

[ShelbyGuy]

The intake port flange on the Nav head is much higher and extends too far towards the center of the block, which prevents non-Nav intakes from fitting on a 4.6 block.

the navi head exhaust port is identical to the 03 cobra head, and the intake port is larger than the 03 heads. cc is .5 point off from the cobra heads and lobe lift on the navi cams are larger. same valves and components per ford and fox lake. i dont care if i lose a few horse i was just wondering if it all can work..thanx for the input guys

 

[nik46notch]

i measured a 04 cobra head and its the same flange size as the navi, it seems like its just the port

 

[GodStang]

More like: Jan 05 heads > late 04 heads (9 spark plug threads) > early 04/03 heads (4 spark plug threads) > navi heads

i'm just being picky

:burnout:

Incorrect 9 spark plug threads NEVER MADE IT IN PRODUCTION.

ShelbyGuy do you know if the Navi cooling passages are the same. I was thinking one of the heads did not have the center cooling passages which made them very bad for Blower applications but this may be the FR500.