5.4L 3V swap, 5.4L DOHC swap, need opinions...

phils95cobra

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Hello Everyone!

I am looking for some advice... My 06 Gt manual is approaching 200K miles and although she runs good, I am looking to do a swap in the not-so distant future and want something different.

Here are the options I was thinking of...

1. Rebuild and stroke out my 4.6 3v to 5.0L
2. Swap out to rebuilt 5.4L 3v
3. Swap out to rebuilt 5.4L DOHC

My goal here is to have more HP and torque, but not a crazy amount. I know I could sink in about 5K or more for a supercharger, but I just don't want to do that. I know that when it comes to best bank for the buck, superchargers are awesome, but I just don't want that route right now. I want to do something different and unique.

I like a challenge. Out of all of these, to me, it seems the 5.4L DOHC from an early 2000's Navigator would fit the bill the best!

I have not concreted my decision, but would like some advice on this.

I know the 5.4 DOHC will fit. I know I will need exhaust mods due to the different placement of the heads compared to the 4.6. I know there may be some mods to accessories, etc. I know that there are probably mods to fuel rails, electrical wiring, etc.

Big questions I have:

IF I go the route of the 5.4L DOHC:

Can I use the stock ECU and get it re-tuned for the 5.4L (Bama, SCT, etc.)

--What exhaust manifold would I have to use? Like those from a 2007 Shelby GT500?

--Regarding the intake manifold, I have seen that MMR makes adapter plated to bolt up any coyote 5.0L intake to the 5.4L DOHC. Could I then use a stock GT500 intake and retain my drive-by-wire for the throttle body?

--How about sensor changes on the engine, i.e. crank, cam, etc.? Would I use all GT500 stuff for this as well?

--Regarding the VVT on the 4.6 3v... how do the cam phasers play into all of this? I know the DOHC does not use this. I have seen this issue brought up on other forums, and wonder how disabling the phasers (i.e. using phaser lockouts) would be any different than them just not existing because of the use of the DOHC engine?

Obviously not the easiest route for an upgrade using the 5.4L DOHC, I know. And I know I only mention the DOHC, but I am not ruling out the other two options either.

Thanks all for the opinions and advice.
 

Dino Dino Bambino

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Hello Everyone!

I am looking for some advice... My 06 Gt manual is approaching 200K miles and although she runs good, I am looking to do a swap in the not-so distant future and want something different.

Here are the options I was thinking of...

1. Rebuild and stroke out my 4.6 3v to 5.0L

This is your best option as it comes without any headaches other than a custom dyno tune. If you're planning to keep it N/A, you might want to consider upgrading the heads/cams/intake manifold to get the most out of the added displacement and higher compression ratio.
Perhaps this will inspire you:

302ci Stroker & HCI
Livernois_302_Stroker.jpg

Combining a 3.800" stroker crankshaft with the 3.554" cylinder bore of an honed 3V block increases displacement from the stock 281ci (4601cc) to 302ci (4942cc). The compression ratio is also increased from 9.8:1 to 10.5:1 when using flat top pistons with 6.25cc valve reliefs. This stroker combination was dressed with Livernois stage 3 ported heads, XFI 127600 SPR camshafts, Livernois cam phaser limiters, FRPP intake manifold, FRPP dual 62mm throttle body, FRPP 39lb injectors, SPEC 12lb aluminum flywheel, and a Shaftmaster aluminum driveshaft.

413.32rwhp 359.49rwtq or 459hp 399lbft (crank)
(SAE corrected)

This represents the pinnacle of N/A performance from a production 4.6L 3V aluminum engine block.
 

RED09GT

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You may not have to swap too many sensors as the cam and crank sensors are the same on a lot of mod motors.

The stock ECU should be able to run it, the tuner will just turn off the VVT stuff, similar to those of us with locked out cams.

You can likely use off the shelf GT500 parts for the exhaust.

Another option is the big bore boss block. The additional bore size is the best way to make power with an N/A mod motor.
 

Forty61

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This is your best option as it comes without any headaches other than a custom dyno tune. If you're planning to keep it N/A, you might want to consider upgrading the heads/cams/intake manifold to get the most out of the added displacement and higher compression ratio.
Perhaps this will inspire you:

302ci Stroker & HCI
Livernois_302_Stroker.jpg

Combining a 3.800" stroker crankshaft with the 3.554" cylinder bore of an honed 3V block increases displacement from the stock 281ci (4601cc) to 302ci (4942cc). The compression ratio is also increased from 9.8:1 to 10.5:1 when using flat top pistons with 6.25cc valve reliefs. This stroker combination was dressed with Livernois stage 3 ported heads, XFI 127600 SPR camshafts, Livernois cam phaser limiters, FRPP intake manifold, FRPP dual 62mm throttle body, FRPP 39lb injectors, SPEC 12lb aluminum flywheel, and a Shaftmaster aluminum driveshaft.

413.32rwhp 359.49rwtq or 459hp 399lbft (crank)
(SAE corrected)

This represents the pinnacle of N/A performance from a production 4.6L 3V aluminum engine block.

Well I’ve found my new long-term dream for my car!
 

Flapjack

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I was one of the first to do a 5.4L 3v swap into an S197. I love the car (when it runs), but it was a pita. Yes, nearly all the sensors match, which is great. You don't need a different PCM or anything. The biggest issue was the intake. I started off with an MMR intake, but that just didn't work out. Justin @ JPC built a few 5.4L 3v manifolds, using their design for the 4.6L manifold they designed (they really only needed to lengthen the runners). That being said, they don't appear to make those anymore, just based on the comments I get from my various YouTube videos.

Personally, I like the 4.6>5.0 stroker idea. That is what I would do if I had to redo it today.
 

eighty6gt

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Holley's aftermarket EFI solutions have come down in price so much the LS based swaps are looking better every day. Check out what Vorschlag is doing. A 6.0/6.2 with cheap ass heads and a cam would blow any modular solution out of the water. Navigator engine!!?

Bob Hanlon has what you need to use your factory 5 speed.
 

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