In reading thru your link post from first of year on your ramps you wrote "I made mine so I have 18 inches from floor to working area. I used 2x12s. You can adjust the height and make it lighter by using 2x10s. I found 18 inches works for me and had that in mind when I built them". So is your ramps 18" tall or is your clearance under the vette 18? If 18 is the clearance how tall is the side of the ramps?