I remember when I was a kid and my dad would take me with him to the local track. He had a buddy that was running a 32 with a big block. He could lift the front end hitting second. He found a set of leaf springs and mounted them something like the way you did. He used a set of wheels off a hand truck. He would put white shoe polish on the wheels each run and we would check to see it both wheels hit the ground or not.