Originals are a type of plastic and tend to be brittle. It doesn't take anything real precise, I have threatened to make some from 1/4" all thread with fender washers and lock nuts top and bottom to retain them. Might have to drill the holes in the top plate a little larger since the original rods were square so fuel more easily flowed around them through the plate. Any spring that takes a couple pounds to compress should do the job.