Secured to your trailer

ultimately you want the body tied down and not the supension. figure out how to put an eyebolt/u-bolt on on each corner of your hotrod. install the same on your trailer. use nylon rachet straps to pull the body down and cross the straps. each strap should cover the weight of your hotrod(dot rule). by pulling the hotrod down you don't over heat the shocks and springs or wear them out prematurely. by crossng the straps the hotrod doesn't move around at all, even if there is a mishap.
I have never had a car with anything but a stock suspension so I have always went to the suspension/axle. A neighbor goes to the frame. He had a strap loosen slightly which allowed the frame to start moving. A short while later all the straps were loose from the car moving ever so slightly. Of course he was in the left lane going 70 mph when he noticed it. Another buddy tows long travel off road trucks alot. He goes to the frame and the suspension/axle. The suspension/axle is to keep the truck on the trailer and the frame is to keep the truck body from moving......