well...maybe... I have a century 125 gl, a lot like the 140, and I built the flatbed and did all the body work on my 59 1 ton and the 47 jeep both of which in my sig. So go look at those - all done with flux core. You can make a welding spoon (see the 47 jeep) that wicks away heat and prevents burn through - and can be used as a 'backer' to just fill in holes with a spiral weld from the outside in. I am only 'good enuf' as far as welding skill goes.
I also have an article on how to build the flat bed in the tech tips section if you want to see more.
