need help on raising bed floor

[blazer2007]

I,m going to try and raise my bed floor in my 78 blazer,has a c-notch with AOL. for now,might change it with the floor.I need to go upp abit to clear the pumpkin and I also want room to run full exhaust as I can,t stand the noise with short ex..The floor is rotten in a couple corners and some of the wheel tubs are rotten as well.I,ve done some looking around and it looks like some people make a grid with sq. tubing and then lay the floor on.It looks pretty simple or am I missing something.These are the only pics I could find but are for trucks