First some information about the stock Springs/Suspension components.
There were Basically 4 types of springs used on the Caprice, Roadmaster, Fleetwood, & Impala SS sedans.
"FE1", The standard, soft springs. Which are notrious for sagging(certainly so on Roadmasters). They are considered floaty, and mushy by many. These suspensions also came with a small 28mm front sway bar, and no rear sway bar. They also came with rather mushy shocks.
"FE2", "F40", and ***(police RPO), The heavy duty suspension used on cars with the towing package, HD suspension package, or the "Fleet" cars, such as a livery R1P Fleetwood, or a Police 9C1/9C3 Caprice. A Taxi 9C6 Caprice. FE2/F40 were used on the tow pack cars, or the Livery Fleetwoods. Where as *** was used on the police cars. These springs are much stiffer, and tend to have a ride hieght that is higher than FE1 springs, or the Impala SS springs. There were slight load rating differences, such as the FE2 springs are one "step" stiffer than the 9C1 springs on GMs chart. These cars also got the large 30mm front sway bar, 26mm rear sway bar, and stiffer shocks. Some 9C1's had optional Bilstiens. The bushings int he control arms mat be stiffer. The body bushings are likely stiffer as well. These springs definatly ride a little stiffer than FE1 springs, but are not objectionaly stiff.
"FE4", the hd, sporty suspension on the Impala SS. Basically the same as a FE2, F40, 9C1 suspension, but the springs had a lowered ride height(more later, when I collect more info)
Wagons Info on wagons to come.
*Note: Drop is listed Front/Rear. These are sets. 2 fronts, 2 rears. Unless noted!!!
Suspension Techniques "ST": $250
2"/2"(not sure from where)
Caprice, 1.5/1.25. Impala SS, 1.25/1.0, Progressive
Impala SS, 1.2"/1.0"
Caprice, 1.2"/1.2", Progressive.
Caprice/Impala SS, 2.0/3.0,
Springs, Sold in pairs.
Global West: $140 - Fronts Only!
Linear Rate, slight drop over Impala SS, Stiffer than stock.
Rustic Racing: $145 -Fronts only!
Linear rate, Drop(check site), much stiffer than stock. 2 different stiffness available.
Rustic Racing: $495 - Rear Coilover kit!
QA1 Springs: $500-$700 - Rear Coilover kit!