The Ranchos on my Dart Sport are RS9114 (old 5 way) I believe the newer 9-way are RS99114. Same size bushings top & bottom. I don't know what the stud size is up top on the earlier cars. I believe the cost around $100.00. But it always helps to shop around. Newest models may be RS999114.
This page may help with specs: [ame]http://www.gorancho.com/assets/catalog/Rancho_Suspension_2010_Master_Catalog_Supplement.pdf[/ame]
There are more race oriented shocks that should work as well. HD, OEM replacements, whether they be for trucks, station wagons or big cars, will still likely be too "soft" to properly control the rear suspension with a high stall converter or a stick.