Go to best buy or even auto zone (I like the best buy ones better) an they have a post you screw into the positive and negative terminals. Cut the wires and crimp o connections on then solder. Done this with two f bodies. One of the best mods I've ever done... You can add as Many wires to the battery you want after that.
It looks like a cylinder the size of your thumb, one end has a stud sticking out, it goes into your battery, the other end has a bolt going into it, so all you do is remove the bolt to undo your battery. Mine is 14 mm so I don't have to worry about stripping it out like the factory 5/16th one.
It doesn't make it a top terminal, but I think it's better. Plus I've had this mod for like 6 years now and never gotten corrosion...