If it is in such dire condition to need a rebuild, it most likely would not have passed smog.

I would personally find out WHY it is consuming excessive fuel. Then I would work on fixing the problem. It will be cheaper and easier than just rebuilding the engine on a whim.

Just a suggestion, I would start with the TBI injectors and see if they are spraying properly. If they are clogged or dirty, the spray pattern can go south fast. Bad spray will equal bad combustion and poor fuel milage.

Michael