What is the differences between 4.6 and 5.4 engines built between 97-98 and 99 – 2001? What was changed to add 15HP to the 4.6L and add 30HP to the 5.4L? Can these modifications be applied to 97-98 engines cost effectively?

 

I'm not sure about the 4.6.L, I did my prepurchase research on the 5.4L because for my needs it is the minimum. The 99 and up 5.4L PI (Performance Inhanced) motor available in the F-150 didn't find it's way to the Expys until the June or July build schedule. The main differance is in the cylinder heads. Also of note, the 25-30 additional HP is accompanied with a very important in a 5,000 pound truck, 20 lbs/ft of torque. I looked long and hard at many full size SUV's before deciding on an Expy. I then looked longer and harder still to find the best possible example to meet my wants and needs.

Petrol
99 XLT 5.4L PI
2WD, 3.73LS, Tow Package,
Load Leveling Suspension

 

Sorry, I think I missed your main question.

As far as I know these modifacations COULD be applied to a 97-98 engine BUT it wouldn't make economic sense. The costof new heads, misc parts and labor would more then outweigh any performance benifits you would get.

If you have a 97-98 you should instead look at what others have done. The serious HP hunters are going with superchargers($2500-$4500 kit only, labor extra). Many looking to spend a little less are very happy with a CHIP upgrade(avail at this sites online store), CAT BACK exhaust upgrades and intake system upgrades (approx $750 and up, parts only, labor extra) If you are handy and have the tools you can do most of these yourself and earn a sense of pride to go with the gains in HP.

Happy Hunting!

Petrol

 

Thanks for the input. I am trying to decide between a 98 or 99, looking at the differences in cost and performance.
Do feel the difference in HP in the 99 is substancial enough to warrant purchasing that over a similar 98?

The configuation of your truck is just what I am thinking of. have you been happy with yours? What kind of mileage do you get and are you driving in flat or hill terrain?

 

Yes I am very happy with my Expy. I found and bought it September 2001. It had 23k on it and 11 months remained on the factory warranty. I paid $18,750 for a truck that, when new carried an MSRP (all options included) of about $32k.

I live in Richmond, VA. I drive the Expy mostly on weekends & my wife sometimes leaves her Infinity at home and takes it to work. On my weekend trip I do alot of Interstate & mountain road driving, ranging from VA to MD, PA, NJ, WV, OH & NC and in all kinds of weather, no problems getting trough with 2WD limited slip rear.

I am almost afraid to admitt how many SUV's (Ford & GM products) I looked at and drove before deciding to get an Expy. I then reasearched (model year/option avail, etc) looked at and drove over 80 Expys. My reason to look at so many, some of which I had no intention of buying for whatever the reason (high mileage, wrong motor, etc.) was to see and answer my biggest questions:

1. I wanted to see how the high milage units were holding up, where were the problems areas to check for, etc.

2. I wanted to see if I could "settle" for a 4.6L or an older, less powerful 5.4L (these are large, heavy trucks and I like to drive, well lets just say I not only couldn't settle, I want more. I guess it's the racer in me (Karts, Dirt & Mtn Bikes heck even things without wheels, Snowboads)

3. I wanted to see if the differances in performance bettween 2 and 4WD (the 2WD is about 400 lbs lighter, sits about 2" lower and YES it is noticably faster and handles better)

It was hard to very hard to find a "used" (just barely) Expy that ahd everything I wanted (we already have 2 vehicals and could take as long as I wanted) but it was great fun and very helpful when it came time to buy as I had gained alot of experiance about both Expys and polished my negoiation skills meeting with all those sellers.

Happy Hunting, find one you like, run a "CarFax"

Petrol

 

Man, you got a great price! Was that from a private seller, dealer, auction? I have a little go fast in my blood as well. I used to drive a race preped Datsun w/ high output turbo system that was a blast. I still have the motor & turbo in storage which I'm wanting to sell.

Thanks for your input, very helpful. I am looking for that happy medium between acceptable mileage and performance. The lower 3.31 LS axle has been recommended to give the best mileage. I don't need to tow heavy loads. Care to trade email addresses? Give me a shout. jdwhite@tampabay.rr.com

 

Yes the price was indeed right (Navy Boy shipping out on the Rosevelt for the Afgan campain) After a quick and through exam I was invited to run a car fax on the guy's computer. I did, it came back clean, I left a nice deposit and the following day returned with a chashiers check.

Axle ratio choice depends. Heavy truck and holeshot says 3.73. Highway mileage in FLAT terrain says 3.31. Personnally I wouldn't mess with 3.31, I think they made 3.55 standard now as well. You also need to consider, as did I, if you are going to upgrade the tire/wheel size in the future and what effect a change in overall dia will have on the ratio.

Your right foot will effect mileage much more then the ratio. The Expy will be much more responsive with the numerically high gears but then there are endless post here regarding mileage.

I'll send you a note on the side with e-mail

Petrol