When building the frame from the start, this is where you have already decided to run the wires inside the frame and install metal conduit (welded at both ends) don't want and loose parts floating around to drive you crazy later... Or; as an after thought, I cut holes in the center of the frame at the points on entry and exit, and run a length of water hose through that area to keep the wires from getting cut by anything inside the frame, then fold a long piece of wire or use a stock wire puller used in home building to get all the wires pulled through.. make your connections and then install a black plastic hole plug the close the big hole, leaving all the wires inside the frame, except where you want the headlight wire holder tube to enter the top? or side of the frame, mine is on the top... also when exiting the frame at the firewall area, and the wires will be coming through the plug, you first must cut the plug from one side to the middle and cut out to the size of the wire bundle, or you could use a stock wire grommet at that point, but I have found the bigger plug is easier to work with... I will look to see if I still have a box of those plugs and give you a part number, they are made to fit different size holes, I use 1 1/4" cut with a hole saw and smoothed with a hand file, inside and out edges...