I installed the CPP tank in my 70 LWB metal floor bed. I'm posting the photos so you can see how the tanks fits in the frame. I don't think a wood floor would make much difference.
BTW - installation is a real PITA doing it by yourself. Get a friend to help with the final installation and bracket lineup.
These photos were before I installed the RideTech suspension. The leaf springs are long gone.
Yours might not have these brackets at the corners.
I cut the brackets out of the corners to get a little extra clearance.
Finished with the RideTech suspension.