I've bought a lot of heads and had them ship to me buy Fed Ex Ground and UPS ground in cardboard factory boxes (Edelbrock's and Indy) as well a s440 Sources shruggy
I bought some used heads that the seller wrapped them up in cardboard with several layers and then tape them up to ship, they arrived fine up

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)