MSD Ignition Pro-Billet Distributor Features: Easy Installation And Provide Powerful Spark Billet Aluminum CNC Machined For Closer Tolerances Provides Accurate Spark Delivery Adjustable Mechanical Advance Vacuum Advance To Help Improve Economy Use w/326/350/389/400/421/428/455 cu in. Engines Must Be Used With MSD 6/7/8-Series Ignitions Height: 18.00 Width: 7.00 Length: 7.00 Weight: 5.50 lbs Vehicle Type: Distributor