Is it possible to use a 5.5ft camper on 6.5ft bed?

In my case the space originated from the fact that my cabover was resting on roof lights and I like the idea of extra storage.
My truck is originally long wheelbase cab & chassis so weight distribution is not a problem.
In your case whole camper will fit on the bed, but still the front gap will be the same and with 5' camper I don't think you will have overload issues.