Yes I did use the original leaf springs and pin. I wanted to see how the truck would launch with these springs. You will need something like traction bars with more HP. My truck was all over the place at first. Makes sure as I said before to relocate your shocks out more, as you can see the other mounting hole in the picture, and also clamp your springs if there is none. Not sure on the gas tank. Also moved the battery back for more weight. If you have a welder, weld all the crossmembers to make it more solid.