The dropped spring retainer cup will lower the spring position 3/4? lower from the top coilover mount. In certain applications this will help clearance issues on the upper mount.
Ridetech 11016510 for 55-57 Chevy HQ Series Rear CoilOver Pair use w/ Bolt-On 4
Ridetech for Rear 4-Link ShockWave / Coilover Universal Mounting Kit
Ridetech 11166510 for 67-69 Camaro And Firebird Rear HQ Series CoilOver Pair
Ridetech for HQ Series CoilOver Shock 6.3in Travel 2.5in Coil Eye/Eye Mounting
Ridetech 11053510 Front HQ Coil-Overs With Ridetech Lower Arms For Chevy Impala
14" x 2" Washable Element Extreme Top w/Chrome Ring Dropped Base Air Cleaner Kit