The stock rear shocks from a f-250 fit just fine on my 05 f-150. They are longer and much stiffer, but collapse to almost the same length as the stock 150 shocks.

The only downside is that the top mount is a little wider than the 250 shock eye, but that can be shimmed very easily.

This stiffened up my rear end considerably and reduced the amount of lean while taking corners with a load on. Hope this helps someone.

 

What year 250? I could liek go to a junkyard and get a really good cheap upgrade.

 

I thought I forgot to mention something. I got the shock off one of the new model (2003?) and up f-250's. The one with the radius arm setup.