Should the bed of a ford 350 single wheel be level from the rear to the cab?

Most truck beds tend to sit higher due to the extra suspension on the rear axle tp handle the load capacity, so it is perfectly normal for the truck to not be level with ground. If you are looking to level out the truck you may have to consider air suspension, a drop kit, or a lift kit. I'm not sure if the rear will have a coil-over spring that you would be able to cut to achieve the same results.