On most truck models you have to install a backing plate under the bed to support
the stress of the bolts when picking up heavy objects or you will bend the metal bed
and pull the bolts through the metal depending on the vintage of the truck. You can
also just bolt it to a larger piece of metal and then bolt that piece down which will distribute
the stress over a larger area of the bed.
Another option is a cable winch mounted in the bed of the truck, you can easily winch a log
up an inclined 2x12 supported on the tail gate of the truck.