I think the smart thing to do is the measure method. Don't like old rubber and sometimes people give the wrong application info and returning thru Ebay is a hassle. Measured front hole to hole Approx 17". As far as bump stop measurement, there is a rubber bump stop at the center of the rear half of front spring. There is also a metal to metal "stop" in center of spring where factory lift spacer may meet a hat bracket on frame. Not sure which one of those to measure. Gotta think about it. As I said, can't really do any real measuring until truck is back together. I have written to others/Gabriel/Monroe/Delco on the web, if I hear back, will post.
