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Discussion Starter · #1 ·
So I did a search but I really couldn't find anything concrete. I don't know much at all about 4V heads as of yet but I have been doing a ton of reading and I'm unclear on a lot of it.

I am going to build a 5.4 4V swap for my 99 GT. I will be using a 99 Navigator block. From what I've been reading that ported B heads are best for boosted applications due to them not overshooting the valves. Will there be problems running the B heads with the Sullivan 5.4 intake manifold? the B heads are made for 16 runner intake manifolds correct?

Would the 03+ Navi heads outperform a non ported B head?

I know that 4V heads will perform better than any aftermarket 2V heads stock so I will probably be running an OEM setup just don't know what the best stock cam combo will be best.

I was thinking of running the Navigator intake cams and Termi exhaust cams in the Navi heads.

Anyways just looking for some insight here. thank you all... and I look forward to moving into the 4V forum lol.
 

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the 97 cobra cams are the highest lift intake cam in the oem cam specs... but the navi heads will out perform any 4v head.. ported all the way out the navi head out flows the 99-01 cobra heads also... and the termis...
yes you can use the 5.4 sullivan intake..
 

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Discussion Starter · #4 ·
So 98 cobra intake cams and navi exhaust cams?

I'm probably not going to do any headwork besides the cams and adjustables.
Is it worth the extra lift? I will be running most likely a d1sc aiming for 20psi what kind of gains can be seen with the cobra cams over the navi cams?
 

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in my cobra motor i have the best of both worlds as far as cams go.. 97 intake and 04 exh cams..
boosted cars see as much as 20hp
 

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yea i know... ive always heard that the 04 exh had the highest lift??
 

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mm's nitrous mod
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the navi heads have dig damn ports in them. if running boost, i would highly recommend the gt supercar cams since they are high lift and made for boost. you can get them for a pretty decent price. the sullivan intake is made for a c head and wont bolt to a b-head. MMR has a new intake for the b-head if you were wanting to go with them. the 5.4 can utilize the larger port design of the navi head, and they would be the head i would recommend.
 

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:no...the springs i the heads will hold up..
 

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mm's nitrous mod
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no, you can get away with it if you on a budget. it would be a good idea on any cam if you pile a ton of boost on top of them. you can get springs at a decent price.
 

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on a 5.4 id think youd be shifting around 6500??
 

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:withhomo.. make sure ur assembly is light
 
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Discussion Starter · #17 ·
No I meant valve train components aren't really boost dependent unless you're talking heat. As long as I keep it cool and under redline I can run as much boost as I want through a stock valvetrain.
 

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mm's nitrous mod
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your boost pressure will effect valve springs. if you pour on a good amount of boost, your valve springs will need to be strong enough to keep them closed so you dont risk leaking boost.
 
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