[huck369]

If you have access to a "Banding machine" you need to "band" it down to the pallet, it can rest on it's oil pan, but it'd be best if you cut some wood blocks to hold it level, mounted under the heads or motor mounts.
If you don't have access to a banding machine, buy a cheap set of ratchet straps to tie it down with....you can hook to any substantial part of the motor, but try to NOT strap across easily bent items.

Also, make sure you drain the oil, and antifreeze out of it (and make SURE the new owner knows you drained the oil)

Making it a actual “crate” is not necessary, and will only add to the weight, so shipping will be higher….strapped down well to a pallet is a very standard way to ship a engine.

Hope this helps.