On the last thread where this truck image popped up, we determined that somebody mounted a frame-forward V8 on a rig designed for launching big boats.* The real engine was under the hood. The rear wheels steer on CV axles like a front wheel drive.
On the launching/beaching vehicle, the boat is floated onto the semi-submerged frame, secured and pulled up the ramp by the ''truck''.
[EDIT] *Floatplanes, rather.
I thought it was photoshopped at first, too.
See:
http://www.67-72chevytrucks.com/vboa...d.php?t=767543