5.4 DOHC vs built 4.6

[THE_KILLER_TOFU]

I've been doing some research over the last few months and have considered several different plans for the engine. The two that I'm most likely to choose between are also world apart in how they fill the HP between our cars and modern sports cars. And for once, I almost have to money to pull the trigger.

- DOHC 5.4. Built, Cammed, Boss Intake. Tried and true and while a bit heavier than the stock block, offers substantially more tq and an improved curve. I realize with the Navi heads, there are only so many intakes that will work. How does one get around that? 03-04 heads should offer a greater range of intake choices..

- Stock 4.6 Built, Bored, stroked, cammed, PRSI(Until I can find/afford a FR500)
I don't know much about this simply because I haven't seen much print material on this build. A few guys running this are on the Corral HP list but there's really no information other than hp and tq numbers.

Not necessarily asking what build is better as that would be entirely subjective, but what would the pros and cons of the above builds be?

[Toby]

I'm new to the modular engines. I'm used to the old push rod motors. The main down side to these engines is the limited aftermarket support. Most people on here will tell you the 4.6 is the way to go. I would prefer a 5.4 because I'm used to the power of a big inch motor. From what I've read, the down side to the 5.4 is the additional weight(iron block), lack of good flowing intakes, and the fact that it's just larger which makes it hard to stuff under the hood. NA, I would prefer the 5.4. On boost, I would choose the 4.6. It also depends on what you want the car for. Daily driver? Weekend cruiser? Track maybe?

[Mach828]

From an NA perspective, seems like the 5.4 swap is expensive, complicated, and not worth it.

I have looked at the NA 5.4 numbers, and a cammed 4.6 based mod motor with a good intake and longtubes makes more hp. And seems like the best way to go.

[Toby]

I'm sure a cammed 4.6 can make more hp than a low revving 5.4. However, peak numbers aren't as important as the area under the curve. Again, engines should be built for their intended use. I agree that it's more expensive to build a high powered NA 5.4, but that's mainly because ford never MADE a high volume, performance oriented NA 5.4. With the exception of the 2000 cobra R, all NA 5.4s were basically designed to produce bottom end torque. Had the 2000 cobra R been produced for as many years and in the same quantity as the regular 4.6 cobra, things would be a lot different.

Since that didn't happen, I'll agree with Mach828 in that a 5.4 swap is expensive and complicated. Is it worth it? Consider this. You can get a lot of power out of a 5.4 without sacrificing as much drivability and you'll probably get better gas mileage too. All depends on what you want. The new coyote engine has bridged the gap between these two engines. I think coyote will be the way to go in a few years, if not already.

[THE_KILLER_TOFU]

Originally Posted by Toby

I'm new to the modular engines. I'm used to the old push rod motors. The main down side to these engines is the limited aftermarket support. Most people on here will tell you the 4.6 is the way to go. I would prefer a 5.4 because I'm used to the power of a big inch motor. From what I've read, the down side to the 5.4 is the additional weight(iron block), lack of good flowing intakes, and the fact that it's just larger which makes it hard to stuff under the hood. NA, I would prefer the 5.4. On boost, I would choose the 4.6. It also depends on what you want the car for. Daily driver? Weekend cruiser? Track maybe?

What you've said is true but understand this is a custom built engine. It will have custom built cams, and the Aussie Boss intake. The 5.4 will fit under the hood, sans shaker but I think you missed the point of the question.

4.6 bored and stroked to 5.3 and 5.4 custom block pros and cons

[4valve 4tw?]

This can't end well. Decide which you'd like to say you have, that's what it comes down to. Personally, for the cost its gonna take to build up that 5.4, you could just supercharge your Mach. Or do some 96-98 cobra cams, call it a day, and keep plenty of cash in your pocket. That and I'm never for adding weight when, plain and simple, its not necessary.

But yeah, this thread probably won't last long...

[iudelt89]

man up and get a 5.0 roadrunner.

[Tommy Z]

Heeeeere we go, ha


Sent from my wifi enabled microwave using Tapatalk

[Fosters]

Originally Posted by iudelt89

man up and get a 5.0 roadrunner.

That's what I'm thinking the best route is nowadays... much better starting point. I have yet to read how they get the gauges running and some details about emissions (in my state it's only an obd2 scan), like which computer is it gonna scan, but other than that, it seems like the way to go...

[Roy]

I dont see where a 5.4 costs more to build than a 4.6. A 4.6 BB block costs about 4 times as much as a 5.4 block. The heads and cams are the same. 5.4 forged cranks are dirt cheap and the pisons/rods cost the same. You can use adaptor plates for the intake. Headers are a issue though. I would build my own shorty headers that pointed forwards. A 5.4 bolts right into a mustang with the K-member shimmed down about 3/4". I never put a 5.4 in a mustang myself and Im sure there is other issues. I did build a 5.4 4V turbo motor for a guy and his mustang had everything other than the AC.
That being said the next motor I build for my car will be a 4.6 BB iron block with a BIG turbo.

[THE_KILLER_TOFU]

Guys,

There's some good info here and please feel free to post more, but think think we're a bit off topic.

The 5.4 DOHC and a 5.3(bored and stroked stock wap 4.6) pros and cons...

Now shoot!

[st0ck Mach 1]

5.3 = Longtubes. you will need them if you stay na

[na svt]

5.4 Pros
-inexpensive power
-can make 400/400 with a stock ported intake and adapter

5.4 cons
-No long tubes available
-adds weight
-can't use the shaker, requires new hood
-have to make new a/c lines
-Boss intake is expensive

5.3 pros
-good power
-lighter than a 5.4
-long tubes are available
-can keep the shaker

5.3 cons
-cost more than a 5.4 that makes similar power


The power potential of the bb/stroker and 5.4 is very similar, but to build a 5.3 the cost will be around $2k higher.