Springs are the foundation of good handling. So start with the best. Put that experience to work for you. Steeda springs are all custom made to their specifications- specifications that have been refined and improved through years of testing. Steeda Competition Springs: Lowers the car approximately 1 1/4" For all out road racing competition Recommended for Mustangs with 351 engine or race weight of more than 3300 lbs Spring rate 850-1050 lbs. per inch Front springs only-Use with Sport or Competition/Street rears