Which motor????

[PapaSmurf03]

So I'm starting my TT build and torn between motors. I'm looking at either boss 302 block or 5.4 block. Not sure what the best heads are either. Motor will be built by a local speed shop. I just need to figure out the block and heads and wether or not to stroke it. Any input or advice is greatly appreciated.

To give you guys an idea of the build it's gonna be twin 6262's from precision, turbo cams, ported heads, return style fuel system on either pump+meth or E85

Searching I've seen a couple guys who have dropped in a 5.4 4valve navigator motor. (built of course) would this be a good option?

 

[03TRKB]

5.4 and never look back. I kinda wish I had went with a 5.4 but eff it. Also Ford GT Heads.

 

[50q's]

That new 5.8 in the 13 g500 is looking great!

 

[PapaSmurf03]

5.4 and never look back. I kinda wish I had went with a 5.4 but eff it. Also Ford GT Heads.

That's kinda what I'm leaning towards now since I could probably get a long block out of a navigator for around $1500 and just the boss 302 block is $1600. As for heads any idea what the difference between 03-04 cobra, Lincoln navigator, and ford gt heads? No matter which ones I get they will get ported upgraded valves, cams, etc.

That new 5.8 in the 13 g500 is looking great!

Yea but how much would one of those motors cost? Lol

 

[cobrasvt57]

Turbo Build

That's kinda what I'm leaning towards now since I could probably get a long block out of a navigator for around $1500 and just the boss 302 block is $1600. As for heads any idea what the difference between 03-04 cobra, Lincoln navigator, and ford gt heads? No matter which ones I get they will get ported upgraded valves, cams,

they say the navi heads need a lot of work on the exhaust and a bit on the intake.The navi intake side is made to be able to feed the 5.4 but the exhaust is a bit undersized because of a divider it has.The 03/04 are nice and will feed the engine but often guys say they'd go ahead and have work done to calm down the velocity of the heads due to the port size and shape.Which in some cases is pretty good for low and mid tq.And the Ford Gt heads are the ringer for all of the heads but in both setups finding an intake for those heads that doesn't cost you a liver would be a wonder.

I'm in the same boat as you right now and the more i look at it i'm leaning towards 5.4/my 03/04 heads P&P/ 10.1 CPR and hold your breath a Boss 290 intake ported & polished.Reason why i was always taught if you build a really top notch N/A build then it only gets better with boost.Oh and 10.1 may get pushed higher since i do have e85 pumps in my area.My thing now is i'm relocating a lot of things the the rear of the car to try to balance this car back out.Anyway good luck with your build i'll be watching from the shadows lol.

 

[Ironhand]

5.4 with FGT heads with my K member.

I have a 5.4 DOHC with HEAVILY worked Navi heads that are on par or alittle better then FGT heads and they are alittle cheaper as well.

I do plan to do a 5.4 DOHC intake in the near future but I haven't quite got to that yet.



Alittle Copy & Paste:

Navigator: (98+ Lincoln Navigator)
These 5.4L DOHC heads feature essentially the same intake port design as C heads, however they have a much larger intake port volume than 4.6L castings. Despite the fact these heads feature a relatively small exhaust port, the extra intake port volume could be very beneficial in helping fill a motor of greater displacement—think 5.4L. Expect slightly better midrange torque, and sub 8000rpm horsepower production than even C heads, however the larger intake port size leaves a slim selection of intakes to choose from when utilized on a 4.6L block. Forced induction fans take note, Navigator exhaust ports feature a thicker exhaust divider (while keeping the same overall exhaust port size as B,C, and FR500 heads) that allows coolant to circulate through this vital area. Conversely however, the larger divider can also hurt flow by utilizing additional space in the port.
The real downside to Navigator heads, when used on a 4.6L based motor, is the severe limitation they impose on intake selection. The physically larger 5.4L heads don’t leave a lot of room (when installed on a 4.6L block) between them for an intake plenum to sit—though they do bolt right up. Remember that since Navigator intake ports are essentially clones of those of C heads (just on a larger scale), they too suffer from the same intake port flaws that plague the earlier tumble port design--no short turn or floor in the throat of the intake port.
The Bottom Line: The extra port volume the Navi’s possess could be very beneficial in filling a motor with greater than 281 cubic inches of displacement, or in high rpm N/A street/strip or boosted combinations. Fans of boost should remember the cooled exhaust port divider. Lack of intake availability is the real downfall of this otherwise wonderful casting.

Navigator head dimensions: Combustion Chamber: 53cc, Intake Port Vol.: 184cc, Intake Port Entrance: 2.290”x1.400”, Valves: 37mm Int., 30mm Exh.


‘03 DOHC head: (‘03+ Aviator, Marauder, Cobra, Mach 1, Australian Boss 260/290)
Featuring a nearly identical (though 17cc larger in volume due to the fact that they are also used on the much larger Australian Boss 260/290 5.4L DOHCs) intake port to the FR500 head, but combining it with a newly designed, larger and more rectangular exhaust port, these may be the best all around DOHC Ford heads ever manufactured. The improvements made to the intake port shape over previous years include a raised port roof and the introduction of a short radius turn in the throat of the intake port that helps assure the incoming air charge finds the combustion chamber. For those with a forced induction street/strip motor, these are without question the best heads available, and as with the FR500s, they should produce great power up to and beyond 8000rpm regardless of application. ’03 DOHC heads also feature higher quality head castings from the supplier, which is at least partially responsible for the modest increase in flow vs. earlier castings--chalk that up to Ford’s revised quality control standards.
Early runs of the ’03 DOHC head fell victim to the same #6,7,8 cylinder coolant flow problems as earlier tumble port castings. In mid ’03 Ford made a running revision to the ’03 DOHC heads that allowed for more coolant to circulate through the affected areas. A blue mark on the driver’s side head indicates an updated casting, and there are no additional revisions to the ’04 version of this design.
The Bottom Line: On all accounts these are the best modular four valve heads currently available. They combine the exceptional flow of a slightly larger FR500 intake port with a gigantic new rectangular exhaust port.

’03 DOHC head dimensions: Combustion Chamber: 52cc, Intake Port Vol.: 177cc, Intake Port Entrance: 1.960”x1.350”, Valves: 37mm Int., 30mm Exh.