Ha, don't I know it! Twins! Congrats, should be good times.
Regarding the 5.4, I just don't see it in my circles as an engine consideration in any retrofit applications. My circles consist of hardcore four wheelers and Ford musclecar performance, often turbocharged or supercharged. I'm not sure why it's not popular, but the DOHC 4.6 is more commonly found in Mustang engine bays than a 5.4.
In any case, not doubting that it's a durable engine, but for a retrofit application where performance is usually a higher priority, it would not be my 1st choice, based on popularity, and aftermarket parts spectrum.
Fair enough I will give you that, they are pretty fat pigs, bigger than a 460! lol. But if you can fit it, why not? Lot's of guys have them in 60's muscle. Shock tower delete and they fit no problem, on top of them being dirt cheap in junkyards right now. My 5.4 in my Mustang should be making 375-400 whp naturally aspirated with probably 400-425 wtq. It's built at this point to handle 1000 hp at the crank and as soon as I can save up the funds will end up with probably a 3.4 Whipple. My truck build will be a twin turbo 5.4 DOHC and both vehicles will be daily driven. My F-150 is my tow rig even. Tons of guys supercharge and turbocharge these engines. Ever seen the turbo Lightning's guys are building? They're insane.
Not sure why you wouldn't love a 5.4 2v in a 4 wheel toy. The bottom end torque is almost unmatched due to the ridiculously long stroke. My 98 150 puts out over 300 ft lbs bone stock at 2k rpm (factory rated is 330 at 2k rpm) and you can feel it, that truck JUMPS. For an 18 year old truck, that's impressive in my book. That's still a damn nice number by today's standards. That 5.4 moves that truck out pretty damn well IMO. Hell if it was good enough for the Ford GT it's good enough for me.
Far as aftermarket what all do you want that you can't find? The aftermarket on the mod engines is pretty decent if you ask me. Years ago yes, I will agree it was pretty weak, but these days there are tons of options. Hell the intake ports on the heads of the Navigator are HUGE and there's really no need for an aftermarket head. The flow numbers are not far off from the Ford GT and Cobra R heads. A little port work and you have a seriously nice flowing head for damn cheap vs what a pair of aftermarket heads would cost. Plus you have the coolant running through your exhaust ports which is a serious advantage over many other heads in other vehicles. For the 2V applications a set of TFS twisted wedge heads and you're ready to rock. I put down 340 WHP NA on my old 4.6 running the 38cc Trickflows and their stage 1 cam on a stock bottom end.
Now yes the 4.6 is more common in the Mustang but that's because it came factory. The only 5.4 was the 300 Cobra R's built. There are plenty of guys who have done 5.4 swaps. Take a look on youtube, guys Lighting swap these cars these days, I've seen the 5.4 DOHC in them too out of the Navi. Course they look like Mad Max with the blower sticking out the hood but they do it haha. I plan on using a TorkTech kit on mine and running a cowl hood so I don't have some crazy thing sticking out of my hood. For now I have an HPS intake that clears my factory hood to run it NA.
I think the 5.4 doesn't respond well to lots of additional power- I don't know about the 4.6. Either will run for 300k+ miles without much issue as long as power is kept fairly stock.
At least that's what I've found in my research while owning a 5.4L.
Respond well how? In stock form? Ask lightning guys with 4-500whp on their 5.4 SOHC. Or the guys with Mustang GT's running Prochargers putting down 4-450 WHP on stock rotating assemblies daily driven. If you're talking bolt on's I do agree, these engines were built so well from the factory there really are not many restrictions that can be taken care of on the cheap. Now if you need more power than 4-500, yes you need to upgrade the rods and pistons, crank is fine though, even the cast crank under 600 hp and 6500 rpm is ok. Unless it's an 03/04 Cobra which of course had a fully forged engine from the factory, those will take much more. Try that with a 302, after 500 or so you need a dart block on top of a rotating assembly, the mod blocks will take anything you can throw at them. That right there is a huge advantage. Don't get me wrong I'm a huge pushrod fan, but what I'm getting at is the Mod engines are not as scary as a lot of people think. Forged cranks came in most 5.4 97-98 vehicles and all 99-01 5.4 DOHC Navigators if you really wanted to go forged for peace of mind. If you're going boosted and planning on a serious twin screw or the like, just tap the crank snout a bit deeper and put a stud in, it it'll be fine.
The 5.4 blows in stock configuration. SOHC or DOHC.
Please explain how this is the case. Again, I'm respectfully asking this question. Hell, maybe I'll learn something and will be able to make my builds even better.
