I have three of these tachs, two with different readlines. I got one on ebay a while back for $100 + shipping. It works great, but they are very hard to see, except at night. I put an Autometer Super Comp tach on the column, covering it up because it's much easier to see and read. Also because I went to HEI. I think that you have to mod the old tachs to accomadate the HEI.