After much looking around the past few days, I don't think it would be worth it for me to pay the the difference for what a diesel costs.

I came across a 5.4L V8. (didn't even know this was an option, until looking wikipedia)
The Excursion is a big heavy vehicle, does the 5.4 get the job done or is it under powered and I shouldn't even waste my time looking at one?

 

Where are you located?

 

In your original post you alluded to maybe someday pulling a travel trailer, if you are now only looking at gassers then keep looking for a V-10 with the possibility of towing in mind. The V-8 5.4 will move the EX around adequately as a daily driver or people mover but it won't be the best tow rig with that 5.4, like you said, it's a big heavy vehicle. The V-8 and V-10 both get very similar gas mileage and the V-10 has more power, and will make for a better tow rig.

 

I have a 2011 F-150 super crew and a V10 Excursion with 139k, I can say having both is the BEST option but not always possible.

Find the lowest mile, cleanest and newest V10 you can afford....that's my opinion.

 

If you can find a any 6.0 diesel excursion that has a good interior and exterior but with a shot up motor for around 6k-7k or cheaper and then pay to get the motor refurbished and bulletproofed you'll have a truck that can last you 600,000 if you due proper mainrence on it and you won't have to worry about huge costs since its bulletproofed.
It will cost you about 6k-10k more to fix up the motor but all in all with a 18,000 dollar excursion with a refurbished and bulletproofed 6.0, you'll have a hell of a durable truck
And if it's an earlier model you can do a front end conversion to give it the 05-07 style that will cost about $1300 for the full kit not including paint
This is what I personally did and have not regretted it because my excursion runs beautifully and I am confident it won't break down even if I punish it.
Also depending on your fuel additive, injectors, tune, and how heavy you are with your foot on your pedal you can get decent mileage especially with the bulletproof. I get about 17--18 mpg on average

 

Also, stated by others make sure it was taken care as best as possible (contradictory to the shotup motor, I know) but also don't buy from a dealer and if you can find a 6.0 in decent condition (that way you won't have to refurbish, just bulletroof) that would be great as well since a bulletproof (if done right) is just a cleaning and upgrade of the 6.0
Note though that bulletproofing involves deleting the cat and muffler by adding a 4" free flow exhaust so it will be loud and depending where you live even frowned upon, however you can choose to skip this upgrade

 

The 6.0 with the 5R110W is your best bet all the way, great low end torque unlike the V-10 which you have to get up to High RPMs to start getting some torque. Plus you can get up to 25 MPG unlike those slow V-10's with the 4 Speed that get like 8 miles per gallon.

 

The 5.4 lacks the power needed to move an Excursion. The gas versions are around 7,000 pounds while the diesel versions are around 8,000 pounds.

Like many have said no matter what year or motor Excursion you could get all will most likely need some upgrades (unless done by previous owners).

Not really a big fan of the 6.0. Ford spent over a billion dollars on warranty work on the 6.0 which led to the termination of Ford and Navistar. After a big lawsuit they parted ways and now Ford builds it's own diesel motor for the Super Duty line up. Know quite a few people with 6.0's who have a lot of problems with them. Of course you can bullet proof a 6.0 to be reliable but budget $5-7K and that's not before a major failure, that's doing it before something breaks! My buddy had a 50K mile 05 F350 dually 6.0 motor fail and after months suing Ford they finally caved in and replaced the motor. Another friend paid $13K for a 150K mile 6.0 03 F350 and last year he figured he had about $13,000 in engine work, 230K miles currently. There were a lot of people who had not one but two lemon buy backs with the 6.0 diesel.

If you don't tow a lot the diesel may be overkill to be quite honest. It will cost more to buy, more to fill up, and more to fix.

The diesel motor to buy would be a forged rod 7.3 diesel which was in all 2000 MY and the early 2001 MY. The PMR 7.3's in 01-03.25 are just fine and if left in stock form will last as long as a forged rod 7.3. They are said to safely handle up to 400HP which is about double of stock (at the rear wheels).

If you can get an 02 with half the miles and half the price as a 05 diesel the 02 looks like a much better option. It's hard to find Excursions with under 100K miles on them.

8mpg towing 4 tons? OUCH!!! Something is not right. I've never gotten below 9MPG towing in my dually and that would be towing 7.5 tons+. Wait, 2 years ago towing the 6,000 pound fish house in a blizzard with a 40 mph head wind got around 8mpg while towing in 4x4. We split the fuel 4 ways so it didn't really both me lol! The 00 Excursion years ago got 15mpg towing 5,000 pounds. The best mileage in that rig was 19.8 mpg. Average is 16-17mpg. The F250's best was 18.6mpg.

As far as miles and repairs,
99 F250 340K miles injector 0-ring seals $700 (2 replacement tranny's)
99 F350 275K miles injector drive module $400 (1 replacement tranny 2 yrs ago)
00 Excursion 280K miles (original tranny)
02 Excursion 310K miles injector replacement $1,900 (swamps) (original tranny)
Diesels in general when they get a little older can have issues starting in the cold. We got down to -20 every Winter and even gassers don't like starting when that cold! For some reason my dually doesn't like starting the cold unless plugged in. The other 3 will start just fine to about -5 to -10 not plugged in.

 

So much info!
I'm looking at v10s but this bulletproofing has got me thinking.

I read some stuff and the gist of it seems adding / upgrading some parts, removing EGR, and labor for a total of about 5k.
1. Wouldn't removing the EGR fail emissions?
2. If one got a 6.0 with 180k + miles for a good price, would it be worth bulletproofing then say paying more for a lower miles and having it done? (is bulletproofing 70k motor the same as bulletproofing 180k)

 

1. Yes it would fail emmisions, here in Oklahoma I don't have that issue because they don't do emmisions checks

2. The only difference would be that you might have to pay extra to replace or fix parts in the higher mile engine because bulletproofing also involves replacing broken or near broken parts and most people that do bulletproofing will insist they replace worn out parts or else they can't ensure you quality. So whether it is worth getting the lower or higher mileage one depends on how well maintained they were. Because someone who punished their truck can have failures at 50k but if someone took care of their truck then it would definitely or at least most likely be in good condition at 200k
If you have a friend who is a mechanic and knows his powerstrokes you can have him come with you to verify the quality of a engine but if not then you can try to convince the person you're buying the vehicle from to have it checked at a shop and if they flat out say no then there is cause for concern there as to why they won't have it checked, especially if you show that you're serious about buying it. The catch there is you have to pay to get it checked most likely

 

Interesting, there must be something very wrong with my not so slow, lifted 4X4 V-10 on 35"s that gets a hand calculated, GPS verified 8 to 9.25 MPG pulling our 11,000lb 41' travel trailer all over the Eastern US usually at 3 to 5 MPH over the PSL. Hmmmmm............

 

Mine too, since I pull my trailer at 70 mph plus over all types of highway terrain.

 

Dude... seriously...

 

It was a stretch to say 8 mpg but I don't believe you can get more than 14-15 (unloaded) because that is what my dad got on his and he is a grandma behind the wheel lol. Also he didn't say it wasn't slow or that it couldn't pass the speed limit just that it couldn't get going of the start like a diesel could. (Not trying to trash you're comment, so sorry if it sounds like that)

 

He's down the street from Tom