Hi all, my 2005 Lariat 5.4 will need a rebuild or engine swap soon.. I never really liked the 5.4 and not thrilled about keeping it... (fuel injector issues, hard to get to plugs, cam slap .. or whatever it is called)... I am looking into replacing it with a 4.6.... I have read it can be done... I have found a shop to do the work, but they have never done this type of exchange... so I want to ask some detailed questions...

I have read there needs to be just a couple of connector mods?

So ... what connectors?
Computer... can I just get the 5.4 computer reflashed? Will the dealer do this? Or is a new computer needed?
I would like to change from a 4 speed tranny to a 6 speed... is this possible? I am thinking a 4.6 and tranny out of a 2009 or newer should work, ... I will need the right torque converter...

Any other elaboration on what will be needed is appreciated...

Also, is there anything I can do to the new 4.6 that would give better performance and/or Mileage? Even if it ran as strong as the 5.4 but got a lot better mileage, that would be cool... I think the 6 spd tranny would help also.... Better performance AND mileage, would be awesome!!! maybe a different cam profile? or anything else internally? And externally, forced air induction, Chip programmer (if so what is a good one?) ..or anything else bolt on MOD?

I am sure I can get some answers here, this forum is great for the amount of knowledge from all us (well, you guys mostly) gearheads!!

Thanks in advance

Phil J

 

You do not want a 4.6 and 6 speed out of a 09/10, it will be a 3 valve with the same VCT as your 5.4 3 valve. It also has a completely different computer and wiring harness. Same would apply with just a 6 speed conversion. This isn't something that can be handled with just a reflash. Dealers can't reflash for mods anyway, a tuning house probably could as long as the computer itself is compatible with your mods. I think you can get a standalone controller for the 6R80, but you are talking some serious bucks by the time you get done.

The 4.6 2 valve has considerably less power than your 5.4 3 valve. There really is no way to get it to make the same power and get any better gas mileage without spending some serious bucks.

My recommendation? Bite the bullet and get another 5.4 3 valve. Starting in mid-08, the heads were redesigned to eliminate the spark plug breakage issue, and should have an improved VCT system. Your 05 was the only year for the bad fuel injectors.

MAYBE a 5.4 2 valve out of a late model van would be a reasonable swap, they never put the 3 valve into a van.

 

Thanks for this info.... Here is my situation ... I am 64 and going to retire in about 2-3 years.. bad timing that my truck is fading power wise.... I still really like this truck and done a lot of customization (see my signature)... So trading it in for a late model average used truck (no way I can afford new) is going to cost a lot because I cannot step down to just a basic/factory model... and pay maybe $20k for something that may already have 80k miles on it... I am not necessarily looking to pinch pennies.... So I would rather refurb my truck, than have to start customizing something I already paid a lot for.. I bought my truck brand new in 2005... and have it like I like it.
So suppose money is no object (not really, but you know what I mean) What would you do? Would you still stick with the 5.4? Would staying with the 5.4 and adding the 6 speed work? Would it be worth the trouble performance wise? Is there anything I can do to improve mileage on the 5.4?
The reason I was thinking on the 4.6, is when I retire, I will be moving farther out into the country.... and a lot more highway /farther driving... I hear the 4.6 runs for a LONG time... If I could set my truck up to get, lets say 300k miles , I may get another 25 years out of it. Since I will be retired I won't have to drive to work every day... heck, I will probably be dead by then :-) My 2005 only has about 220 on it, and I drive almost every day.... again, not looking to spend money foolishly, but this is to set myself up long term... so paying more up front, I am ok with that.
That said , what would you do? Heck, I would install an ECO-boost if I thought it would work, and give me better mileage :-)

Thanks

 

Again, a 6 speed is not really feasible. It has a completely different wiring harness and computer. Get another 5.4 3 valve, mid-08 or newer with the revised heads, lock out the cam phasers, and get a custom tune.

Anything else will get more involved (and expensive) than you probably want to go.

You aren't going to get good gas mileage no matter what you do. The truck is just too heavy. A 4.6 is just going to be a dog.

 

Thanks

 

Personally, I recommend doing one of two things:

1. If you have that much disposable income to throw at modifying different transmissions and electronics to make it all work, then at that point, I recommend buying a new truck - especially if you need reliability. For fun it's one thing -- but if you need a serious ride, for say work, then it's not going to cut it.
2. If you choose to keep the 5.4l in there, I highly recommend staying with the 3v, and bulletproof it. There are a lot of folks out there that have successfully bulletproofed their 3v for longevity and reliability. Along with a bulletproofed tranny.

There are a slew of vendors you can work with to sell you a crate engine drop-in ready that is already bulletproofed, tested and dynoed. There are plenty of folks on here that can help you too.

With that being said, take a look at the 6.4l PSD in the SD's from earlier years. Those engines were interesting - reminds me of the 5.4l, but in some instances made the 5.4l 3v look more reliable. In any event, folks that bulletproofed the 6.4l PSD, are very happy with the engine and it's performance. Not to mention it's reliability. A LOT cheaper than trying to stuff a different model year engine under the hood.

 

What would I do? Simple, I'd be looking for an 1988 to 1997 F150 that has the 7.4L/460 EFI engine. I want the whole truck so that I get engine, transmission, mounts, brackets, ECM, radiator, everything. I'd rebuild the engine and transmission taking my time while I drive the tired 5.4. Swap is relatively easy. Those engines were near bulletproof, tons of torque, and could get reasonable gas mileage if you drove it like you had common sense. Then part out the rest of the old truck getting a lot of your money back.

 

Problem with that is, the 460 was never OBD2 and the E4OD is a very old transmission design.

 

YM 1996-1998 460's were OBD compliant not that I see that as any advantage or disadvantage. I raced the 385 series engines all the way back to the mid 70's. I even had a 385 series blown in a jet boat making 2800HP with the rev limiter set at 10,000 rpms. The engine is solid as it gets. I don't see where the transmission design means anything. The best transmission to ever sit in a car was the 727b and the design is still in use today at over 50 years. Most of the boat racers and a lot of the drag racers still use the Powerglide transmission, yet another 50+ year old design. I ran numerous Powerglides over the years in the drag cars. Pretty solid design I'd say. Just cause it's old doesn't mean it isn't great.....kinda like me and you.

 

The way I see this is you got 15 yrs and 220k miles out of the original 5.4 3V. I would just replace the engine with a reman and get on with retirement. Like you said you won't be driving as much in retirement so why go to all the expense of modifying the truck. It's going to be very expensive to do so.

 

Just try to get a reman with the new head design.

 

Delete, double post

 

With the infrequent spark plug replacements, that may not even be necessary. Would a reman with the new head design require modifications to get other components to get it to work?

 

I don't think there would be any major mods required.