Barry: there is about a half inch of space around all sides of the vac when it is on the dolly. If I was less lazy I could glue some chunks of foam or something in there to make it a snug fit, so that the dolly would stay "attached" when I lift up the vac.
The motor on mine still has the cloth bag over it, and over that I have a HEPA bag. I bought some HEPA bags for a large upright vac and then cut them to fit. We use the heck out of this thing. It is the only canister vac in the house that can pick up all the hay and feathers in the pet room without the hose instantly getting clogged. It was my first vintage vac and the only one I couldn't live without!