How To: F350 Blocks on a F250

[riggz]

DC Special asked me a while back to add this over here, (initially wrote it for Ford forum) and I forgot about it. So here it is, years late!

DISCLAIMER: I recommend you have someone with you for safety reasons. This can be done with one person, but have someone nearby just in case. You are responsible for your own safety! I will not be held responsible for any damages incurred. If you don't feel comfortable with doing this on your own, have it done by a professional! There are numerous ways to do this. This is one way to do it with limited resources.


If you have one of the following:
Crew Cab Short Bed (156" Wheelbase)
Super Cab Long Bed (158" Wheelbase)
Crew Cab Long Bed (172" Wheelbase)

Then use these part #s:
Blocks: F81Z5598DA x 2
U-Bolts: N803770S436 x 4
Nuts: N620485S441 x 8 (You can reuse the old nuts if you wish.)


If you have one of the following:
Super Cab Short Bed (142" Wheelbase)
Regular Cab Long Bed (137" Wheelbase)

Then use these part #s:
Left Tapered Block: F81Z5598FA x 1
Right Tapered Block: F81Z5598GA x 1
U-bolts: 5C3Z5705AA x 4
Nuts: N620485S441 x 8 (You can reuse the old nuts if you wish.)

If you want to shim the drive shaft:
3 1/4" Shims: EOTZ4A209A x 1 (Comes with 3 1/4" shims. If you use more than 1 shim, you will need longer bolts. Most people only use 1 shim.)


Tools:
2 jack stands or bottle jacks
2 floor jacks
15/16" deep socket
18mm socket (if you plan to swap out the rear shocks)
Torque wrench
WD-40

Here's what the new F350 parts look like:


Step 1:
Park the truck on level ground and chock the front wheels to prevent the truck from rolling.


Step 2:
Position your jack stands or bottle jacks so that they will support the rear leaf springs just in front of the bottom leaf.



Step 3:
Raise the rear axle with the floor jacks high enough so that the rear tires are at least 1-2" off the ground. It's not recommended to lift with the differential. My 2nd floor jack was busted, so I took the risk. (I also used a hi-jack lift for added safety.)



Step 4:
Raise jack stands or bottle jacks to the point where they touch the leaf springs, but do not raise the axle.

Step 5:
Remove rear wheels.

Step 6:
Spray WD-40 on the u-bolts & nuts to loosen them up.

Step 7:
Using a 15/16" deep socket loosen all 4 nuts on each side, then remove them.

Step 8:
Remove the u-bolts.



Step 9:
Remove the top plate



Step 10:
With the jack stands or bottle jacks in place, slowly lower the floor jacks so that the axle drops and there is enough room to install the new larger blocks.



Step 11:
Remove the F250 blocks and install the F350 blocks. *Note: If you have the tapered blocks, the smaller side of the block faces the front of the truck.*

Step 12:
Slowly raise the floor jacks up to where the new blocks are just barely making contact with the leaf springs.

Step 13:
Reposition the blocks so they are straight in line with the axle and leaf springs.

Step 14:
Raise the floor jacks so that there is enough pressure on the blocks that they will not move.

Step 15:
Install the F350 u-bolts and nuts into the top plate using a 15/16" deep socket. *Note, you may need to tighten them down at the same rate to prevent one side from being over tightened. Torque the nuts to 185 ft./lbs.



If you have either of the two shorter wheelbases here is what yours should look like:



Step 15a:
If you are replacing your shocks replace them now. You will need an 18mm socket for this step. Torque to 46 ft./lbs.

Step 16:
Put the wheels back on.

Step 17:
Raise the floor jacks off the jack stands or bottle jacks, then remove them.

Step 18:
Slowly lower the truck back onto the ground and torque the lug nuts.

Here is the difference in height the F350 blocks provided (approx. 2" of lift):

Before:


After:



And for comparison purposes:


(F350 Block on the left, F250 block on the right)