I wasn't sure Tom. Your Impala has the ride heigth of the standard Impala with AC and 8-25-14 tires or 8-25-15 with disc brakes. the heigth is 4 3/8 +or- 1/2 inch. Every difference like 4 speed without A/C has a different spring. You are better to keep Your original springs and shim them. Radial tires do make a difference also, ride lower. Any after market spring will be a hit or miss. How high and stiffness of ride. 14 inch tires had a softer spring then 15 inch. My car rose 2 inches when I pulled the 427 and installed a 327 with 4 speed and no A/C with 15 inch bias ply tires. Station wagon spring will give You the same lift. You will need wagon springs on the rear then. Good luck with the Moogs, probably their heavy duty springs. NICK L72