Is anyone using big block coil springs on a 65-66? I'm thinking of removing my 600 lb springs and replacing them with a taller spring. So far it looks like I'll try the '67 springs for a 390 and cut a half a coil if I need to. I want a little more clearance on the front. I haven't seen a 600 lb spring with stock height in the cataloges I have. The occasional rub, from the shelby drop and the springs lowering it too, is starting to get to me. Any other ideas? What are the spring rates for the 390 or the 429 with ac? Thanks.