[misfit41]

I am currently redoing a shell valley car as well,get your self a jegs or summit catalog,floor mounted pedals arent that expensive and will look much more correct,I have the sv set up which I am moving from the top mount to the floor,the setup is simple and wouldnt be hard to fab if you can cut and weld,an extra master cylinder and swinging assembly should be all you need.I would steer away from the mustang set up,for the same amount of work,you can do something that looks much better.
There is enough space if there in the right place,just takes some trial and error to get the angles and spacing correct.
I also suggest getting all the cobra parts books,finnish line,cobra restorers ,etc,lots of the parts are sold in components.
good luck,,Tk