I have been know to be thrifty with straw walker blocks by sanding down the flats wher the bolts go thru to tighten them up. If I remember right I took more off the top blocks and turned them over putting the better blocks on the bottom. Ran about 300 acres that way. When putting in the new set had to shim a few apart using some thin sheetmetal to keep them from being to tight. Good luck