Get a box big enough to give it at least 3" of clearance on all sides.
Put it in a garbage bag, suck the air out, tie a knot.
Set it in the box on something so it's 3" off the floor and equal space from the walls.
Spray-foam the bottom of both ends, let it expand and harden.
Spray foam the middle-region on both ends less, since now you know how much it will expand.
Spray foam the top on both ends using that collective knowledge so that it will fill the void and then some... and close/seal the box before it hardens..
It will arrive undamaged; and the receiving end won't have a mess to unpackage.
If you wanna be a pal, draw a dotted line around the center section and label it "cut here with razor knife and separate halves".
I package used cylinder heads and radiators this way, and have never had a problem; even UPS ground.
I sent a crystal vase to my mother this way as well; non issue.