I packed some pieces at a power plant they was pieces from the scr unit and used the instapak stuff works nice it has a bag inside the outer bag you bust and you bust it and put in box
The old Rubbermaid "Action Packer" from walmart was good enough to ship xr600/650 engines routinely--real tough plastic casing, and basically cram the open spaces full of "whatever". the new Action Packers aren't as tough though...