make it my own

[LAMBO]

Hi forum, I have a 1972 Chevy C20 that I purchased 2 years ago. Now it's time I make some mods. I was wanting to lower it and was checking throughout the forum but I still have questions. What does 4/5 mean? Is it inches dropped in front and back? I have coils in front and leafs in back. I was looking for a axle flip kit but can only find them for the C10. Am I looking in the wrong place? I've heard that re-arcing springs could lower it too but does anyone know how much? Or do I take out a leaf or two? I won't be hauling anything with the truck either so I don't need to worry about losing cargo weight limits.
And for the rims, what is the process of converting it from an 8 lug to a 6 lug? Is it expensive?
Thanks for any help.