I don't know where to find lead blocks(small). I imagine off ebay or internet store or supply place. I could also buy large ingots, which would probably be cheap. But......Creative Engineering brought up a good point. I never really thought of how lead would constantly deform under pressure of mounts. Ironically, I came to lead after buying sorbothane(50 durometer visco-elastic polymer). I found out about sorbothane because a guy on ebay was selling it for these engine kits. After installing it on my bike the pressure from the mount cracked it and it fell apart. That sorbothane was a gimmic! So, after that the guy closed his business(it lasted a few weeks) and I tightened my mounts so tight that I broke the mount. I had some strong steel strips lying around so I cut and drilled a new mount. It was so strong that I bent the bike frame! So, now I don't really have bad vibration, but I'm just trying to improve my ride by making it more comfortable. I think I'll look into high durometer rubber because Creative Engineering implies that it attempts to maintain its shape; it should also offer more support than medium durometer.