Maybe the old springs were arched? Also, there are tons of springs that have been sold over the years that make the car higher than stock. My experience with Eaton (springs) is if they say they are selling stock height leaf springs the car will sit at stock height. A first gen at stock height will not accomodate 275 tires. If you want to run 275's then my advice to you is to take your leaf springs to a business that knows how to arch them. They will warn you that it may shorten the spring life and lead to broken springs. Sound familiar? Maybe that's why the springs you had that would accomodate the huge tires were broken.
