On a single rear wheel truck, the rear brake shoes are 3" wide from the factory on the 350, drums are the same between the two though. A pickup dually has a wider rear axle, and the dually hubs on the front. I'm not sure if it's the dually that has the larger wheel cylinders or just the 350's in general(the SRW's aren't that common) but all the bigger stuff bolts on the 250 no problem.