To date i have discovered the following Rear Springs part numbers are installed on 2008-2015 F250/350SD trucks:
BC3Z5560-E
BC3Z5560-F
BC3Z5560-G
BC3Z5560-H
BC3Z5560-J
If anyone can help identify the Ford OEM Part Number installed on F250 Pickup(s) with 6100 rating@ground 3 leaves 3.28 total thickness 324/782 deflection rate 2695 rating@pad will install without removing 'overleaf aux spring and spacer' - footnote (8) as listed on the pdf

... i would appreciate a reply.
A answer may be - "since all of the springs listed are 3 inches wide and 66.3 inches in length simply find the lowest cost and modify by removing overleaf" and that is a correct reply.
My plan is to start by determining the ideal fit off the shelf first.

 

Any SuperDuty rear spring pack with a factory TOP overload and spacer will need to have that top overload removed to mount the springs on an EX. The EX doesn't have the frame mounted landing pads for the top overloads and that overload leaf can hit the rear AC lines under full compression.
Also, the '08+ truck rear springs are longer than the '99-'07 version, so using those newer springs will require you to remove the front spring hangers and install a new set, there are kit$ available for this.

 

Just curious, why do you want to run the longer springs from the newer trucks instead of the ones that will bolt in without moving the mounts ?

 

Just curious, why do you want to run the longer springs from the newer trucks instead of the ones that will bolt in without moving the mounts?
Great Question pirate4x4!!!

The answer is that i am following Ford Engineers and their decision since 2008 to lengthen & soften & strengthen the rear spring and widen the mounting location on their frames.
I expect softer ride with less spring wrap while adding payload/spring capacity.

Perhaps in the future: adding rear sway bar and/or traction bar and/or air bags
but starting with the main component first.

As the original owner, this vehicle has been babied = first ten years less than 10,000 miles carrying customers to tailgate ... cringing every time i tried to slowly drive/ride over any turn with any elevation (like a entrance into a parking lot) because the EX wanted to head snap my passengers spilling drinks.
After the baby years this Ex has been driven off road many many times pushed to extreme into and out of locations ... all bump stops were destroyed, and then i cut out section of the roof adding fiberglass top converting into travel trailer tow or off-road camping vehicle removing everything but front captain chairs (searching for swivel seat mounts for front captain chairs!!!)
Only maintenance/work to anything under the floor over the 16 year 240,000 mile service has been tires, fluid, lube, grease, replacing shocks, ball joints, and warn hubs.

For years i have been "lurking" Ford Truck Enthusiasts and Supermotor Forums reading everyone's spring mods, shock mods, radius arm, sway bar, traction bar modifications and appreciate everyone who has contributed.
My turn to contribute, so unless someone alerts me "Warning ....Do Not Change to the modern Rear Suspension!!!"
My plan is "out with the old" and install the newly designed rear springs.
Here is picture of the new Rear Spring Hangers.

 

WARNING no need to change to the 08 length spring to accomplish your goals.

 

First Thing to clear up.

we need to establish the main role of the spring. the springs job is to hold up the weight of the vehicle and the payload.

Your ride quality is going to be determined by your shocks. and that is a different although related discussion. for now lets focus on your springs and holding up your excursion.



Lets start by looking at a simple comparison of the 3 springs and in the case of the f250's we are talking about the primary spring pack with no secondary springs ( that your Ex would require mods to use )

1. ford excursion 99-04
5.5" inch travel. 410 Lb inch spring rate 5252#ground rating

2. Ford F250 99-04
7" travel. 320 Lb inch spring rate. 6084 ground rating

3. Ford F250 2008 +
7' travel. 324 lb inch rate. 6100 ground rating


So the first thing you will notice is the Excursion spring pack is actually a stiffer spring then the F250.

second thing to note is the F250 has more travel, and why it provides a lift when used on the excursion

third, you see the 99-04 springs and the 08 springs have the same spring rate, travel and load capabilities.


going back to your expectations of
I expect softer ride with less spring wrap while adding payload/spring capacity

1. softer ride. SHOCKS.

2. less spring wrap. if you are actually using your excursion in a way that spring wrap is causing the wheels to break traction and shudder when they wheel hop then you need a traction bar, if not then "spring wrap" is being controlled sufficiently

3.Added Capacity.

The simple answer here is Air bags. and the reason they are better is simply because you can adjust the spring rate to match the vehicle and payload weight.


You didn't include Added suspension travel or additional ride height into your expectations but from the rest of your story it would seem that would also be an expectation. in which case you could either use the 99-04 or the 08 springs as the basis of your modified spring pack. Even if you change the mounts and use the 08 spring you will need to add leafs to the pack just the same as using the 99-04 leafs. Bottom line is your excursions weight is going to dictate that your main spring pack have a 410 SPRING RATE.

once you modify the F250 spring from 320 Lb in. to 410 look at the capacity.

320x7 =2240
420x7 = 2870

break...

 

@lee

From your message it sounds like you are wanting more info on the subject then most folks might care for so I'll steer you to SAE HS788

Basically the engineers handbook for leaf springs.
*** warning, large PDF down load
http://allaboutmetallurgy.com/wp/wp-...n%20Manual.pdf