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The pistons are different for the 2v vs.the 4v heads, the have different valve reliefs cut into them, also the 3v heads have their own special pistons. it would not be worth it to swap the heads and pistons for just 40 hp. I would stay with the 2v heads and nurse it for as long as you can. Pick up the complete navi engine and fix it, maybe even hop it up some and have it on standby for when your current engine goes caput. If you have to drop the pan and swap out pistons to do a correct 4v head swap, it's the same amount of work to just fix the navi engine, unless the block is damaged.
 

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Discussion Starter · #22 ·
Not really after performance as i am efficiency. My truck lists mpg as 14/18, an 01 navi lists 13/17, but the navi has a good 600 lbs more weight. My truck currently sits at 5720, with half a tank of fuel. I put my handheld tuner on my truck, but its only a canned tune for now. I haven't run it long enough to tell the effectiveness of it. Ive got it set at 10* retarded 0-2000 rpm, 4* advance at 2000-4000, 3* 4000-8000. Cruising speed 70 mph is about 17-1800. I've read some get better mpg at 75 than 70.
I'm also thinking the engine will get better efficiency with less load, so a switch from 355 to 373 might be in the future. The sport trac did awesome for towing, having the same trans, but different internals, but with a good 60 hp/100 tq less. I'm at the transmission's power limit without a rebuild with stronger internals, and I think I'm getting torque converter shutter. Every once in a while I feel it. Thinking I may go ahead and get a navi drivetrain, research what mods I can do to make it more efficient, like better rockers, low drag rings, etc.
I also gotta look at my rear axle better, I just might have the 9.75. I was under it yesterday looking at my exhaust, which needs attention, and it didn't look like an 8.8...

SVT
 

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Discussion Starter · #23 ·
Gotta pull the cover for that. I'm sure the tag is still on the cover, just haven't got my butt under the rear to check. 2k was good for the trac as well, but the problem was 2k came at 60. I've thought about swapping in my teksid for better mpg, but it was easier to fix the stripped plug...

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Since you have a 5.4 and rear discs, I would bet a dollar to a donut that you have a 9.75. All 5.4 equipped trucks are supposed to get the 9.75, also I don't believe you could get rear discs on an 8.8 until the 2004 redesign. But ford has done some strange things before.
 

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Discussion Starter · #25 ·
I seen a 97 8.8 with discs, didn't believe my eyes when I first seen it. And thats what I thought about the 5.4, it got all the heavy duty stuff. Correct me if I'm wrong, but the 9.75 would of given me the 7700 payload, right?

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Correct me if I'm wrong, but the 9.75 would of given me the 7700 payload, right?

SVT
I don't know, on the 2004 up models the Heavy duty package or 7700 model got a bigger 10.25" axle with 7 lugs. I'm not not very educated on the build details of the 97-03's, never owned one. I'll research it a little and let you know if I find anything. Shane may know more.
 

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Discussion Starter · #27 ·
I know the 7 lug trucks of 97-98 were considered 3/4 ton, but had the F150 cab...

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Discussion Starter · #28 ·
I'm finding the 7700 was 7 lug, and had the sterling 10.25 axle, but I can't confirm that yet...

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I found this on F150online

and some facts about the 250LD/F150 7700

- 7 Lug Rims -
- They have a larger frame then the F150
- Bigger Brakes
- 3:73 rear end from factory
- 4R100 Tranny
- Extra leaf in back
- Larger Torsion bars -
- Heavier towing capacity
- Weigh more -
- Larger rotors, I believe 13.5"
- HD shocks
- power steering cooler
- 4700 lbs rear axle
- HD rad, thicker
- HD alternator
- HD battery
- LT tires standard, load range D
- the tranny is the same as a F250 SD and the F350 SD
- 8,600 lbs towing
- 11,500 lbs GCVWR
- 7,700 lbs payload

also everyone says it has the 10.25" sterling axle.
 

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Discussion Starter · #30 ·
Thats the majority of where I'm getting my info...

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Discussion Starter · #31 ·
Well, I finally looked under my truck and sure as daylight I've got the 9.75. So I guess I'll just get a set of gears and front axle assembly from an expedition to go to 3.73. Frame's in good shape, but the bed is rusting. The exhaust is as well, but its that cheap pre bent pipe that goes over the axle, and it reduces down to 2" diameter. What I don't like is its 2.5" in, dual 2.25 out. I would prefer it to be 3" in. I might change it out latwr on to a single muffler dual 2.5" in, dual 2.5" out. For now I've got 2 stainless pipes with a 90* bend in each, I'll use these to turn out and exit in front the rear tire, like all my exhausts are done. I'll reuse the chrome tips and do a lightning style dual tip. I'll do this Monday...

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Discussion Starter · #32 ·
So the exhaust is done, lets take a look at what it took...
First, I knew I was going to need an exhaust hanger. I just happened to have one, couldn't tell you where or when I got it. If you ever have to do exhaust work and need a hanger, I highly suggest you get the heavy duty one, I've done way too many exhausts to know the regular one at the parts store doesn't work for long...



Here is just after the muffler, notice how one pipe rusted through, separating. The other pipe broke loose and almost separated completely due to a hanger breaking from rust...



This is the pipe before the muffler. Can you tell they used cheap pipe?



Once I cut the muffler off the truck, and the pipes off the muffler, this is what the muffler looks like. This is a flowmaster knockoff, and it shows. I'll be using this for now, but it will get replaced soon...





Here is one of the tailpipes where the chrome tip was. This is what the pipe looked like when I cut the tip off. These tailpipes are the prebent pipes you get from any exhaust shop, they use these to save time, and money. If you ever get an exhaust done, tell them NOT to use the prebent pipes, you will spend more money and time, but it will last, unlike these...



Here are the stainless pipes I got from the junkyard when I picked up the sport trac bed, they are 2.5"...



Here the pieces are laid out and cut....



Here is where I started getting rained on, so I rushed to get it done. I prefit the muffler on the truck, and positioned the stainless pipes where they needed to go. I was able to weld the pipes to the muffler out of the truck, and I wanted to do the tips the same way, but with the rain, I welded them on the truck, so the tops of the tips and the top of the muffler on the input side was not welded (unable to reach without the truck on a lift). The muffler was a tight fit on the input side, so it didn't leak...





Overall its actually slightly quieter than the previous setup, but then again it was leaking right under the truck. I plan to get a dual in, dual out muffler, separate the exhaust where the factory Y pipe is, and run them side by side into the muffler. Should run a little better this way, going to get a stainless muffler as well...

SVT
 

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Discussion Starter · #33 ·
I knew the V6's got side exit for 97, didn't think it was standard. Oh well, my version of lightning exhaust, lol

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I read that the side exhaust the moister got onto the rear brakes and stuff there and it rusted stuff.
 

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Discussion Starter · #35 ·
I do side exit exhaust on all my trucks. I've had no issues...

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Discussion Starter · #36 ·
Yeah, think I'll do a vid clip of it. Sounds like a 3 chamber flowmaster, very mellow, but a good deep sound...

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Discussion Starter · #37 ·
Doing great. Whats been going through my maniacal head? 4.6l 4 valve swap, navi engine swap, or go for a coyote swap. Coyote swap would give me more power, but would also give me more efficiency, which is my ultimate goal. Also been looking at brake upgrades as I'll need rotors up front next brake job...

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Discussion Starter · #38 ·
Have you done this? What year, the 97-03? I was looking at the 7700 brakes. There is a big brake kit for our trucks, but I don't have an extra 3k laying around. Wonder if the 04+ expeditions are any bigger/better...

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Discussion Starter · #39 ·
Guess I'm grabbing some caliper brackets next time I'm at the junkyard. I was going go order some powerstop slotted rotors from rockauto, but the pads are going to be AutoZone's top line pads, since they have a lifetime warranty...

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Wonder if the 04+ expeditions are any bigger/better...

SVT
The 04+ brakes are 6 lug, just like the 04+ 150's 6 x 135 mm pattern.
 
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