What are the major differences between the 250s and 350s these days? IIRC the spacer block was the only real difference in past versions.

Given the current incentives in Canada, it just may be time to move up from my 05 250PSD.

I'm thinking I'll be going to a gasser this time around; the 6.0 has tamed my diesel lust.

 

Not sure of the specific rear spring differences. But I do know that the 350 has a beefier rear axle and hydro-boost brakes where the 250 has vacuum-boost.

I changed my order to the 350 and it only added a couple hundred bucks. Well worth it imo.

 

How exactly is the 10.5 in the 350 beefier than in the 250? DRW trucks have a Dana axle in them, but all SRW trucks have identical axles. To my knowledge, the whole "axle shaft diameter and sline count" myth hasn't been proven by anyone here by actually pulling an axle shaft on a 350 SRW and comparing.

 

You can compare the differences at the link below.

2011 Ford Super Duty | View All Ford Super Duty Specifications | FordVehicles.com