If the dealer isnt to far from you, I say go there and get the vin off of a truck that has the axle and ratio you want and get them to look it up for a price.
You would need all of the steering linkage and maybe trac bar.
. . .
Its a pita to use, but fordparts.com can be helpful in getting an idea on parts prices.
Its going to require something to keep the same lug pattern on both axles as well. Maybe change the hubs on the rear and if you can go with the bigger brakes. Some years 450 chasis cabs used the dana 80 so parts may swap over.
Aaron
The '11+ F450 Pickups use the same axle and 8x200mm bolt pattern as all the F350's have since '05. I wouldn't mind the extra braking of the conversion to a 10 bolt setup, however I want to keep costs down and not be limited by the small selection of 19.5" rims and tires.
Just post in the Sunrise Ford thread and see if Britt can hook you up!
Now you got me thinking about swapping in some 08 and up F-450 axles in my 03!!
Been researching, and I read the center sections are the same.
The Front Axles Ratings and bolt pattern of the 'fatboy' F350's of '08-'10 and the '11+ F450 Pickups are all capped at around 6K depending on the spring package.
I've also looked at the steering box, both the F350 and F450 (pickup) have the same ratio in the steering box 20.41:1. (I believe this is the same ratio as my current setup, but I will verify) Which means I'll just need the pitman arm, and linkages out from that, not a new steering box itself.
I am coming closer to a full parts list of what I may need, though I haven't found parts numbers or prices of all of this just yet.
I appreciate all the help I am getting with this unique project. If any members have, work with, or can get a picture of the F350 'fatboy' or '11+ F450 Pickup's Front Axle where I can see all the linkages and everything, I'd appreciate that as well for cross reference purposes.