I would say, for the most part, just identifying the vehicle as a Ford E450 will get you the proper part. A more specific definition would be a Ford E450 on a cutaway chassis. Some parts, such as shocks, will have a separate part listing for the cutaway chassis. If you can, take the old part with you when you?re purchasing a new part. If ordering online, try to utilize a retailer who provides a picture of the part. When I replaced the power steering pump on my older E350 it turned out the pump was actually one specified for use on Ford diesels. So, a little caution would be in order when replacing parts. By the way, I use RockAuto.com to purchase parts as they have actual photos of the parts they sell and list the cutaway chassis in their vehicle identification chart.