Rear suspension help; soften and raise on 1939 Buick Special hotrod

Hi Folks,

I'm looking for some rear suspensions advice. I have a 1939 Buick Special hotrod. The rear-end is from some 70s-ish Ford (currently unknown) and is comprised of two large coil springs and shocks. The springs are about 18.5" long uncompressed, 14.5" long with the vehicle sitting on the ground, a spring diameter of about 0.65-0.7" and an total diameter from the outside of the spring of close to 7". The current shocks are Gabriel Guardian (part #: 81878) with 17.7" extended, 11.2" compressed and 6.6" stroke length.

In an ideal world I need to do two thing.
(1) soften the ride
(2) raise the rear-end about 1-3"

I've looked for other coil springs that are longer, I found some from MOOG but their have a very high spring rate and would likely make the ride much stiffer. I have considered going with something like RideTech 8000 Series ShockWave, but they are expensive!

Any suggestions would be apprecated. Thanks!

Links:
- shockwaves: ShockWaves :: Universal Styles - RideTech.com - Suspension Specialist - Online Store
- current shocks: Gabriel Guardian/Shock/Strut - Front (81878) | AutoZone.com
- mood springs: Moog Suspension Parts - Universal Coil Springs

Find a parts store that has real catalogs and not just computers!!!! They should have a parts book that lists spring by the configuration of the ends, their rate, diameter, and length. Then it's a matter of finding a spring with the same ends, more height, and a softer rate. My Napa guy and Car Quest guy here locally have both been in the parts biz for years and have copies of these "good books"..... Don't bother with the likes of AutoZone and other chain stores, if it's not in the computer they're clueless!!!!

Another alternative is Eaton Spring Eaton Detroit Spring Home
They can custom build to your needs. Folks who have used them report how savvy they are, and not as crazy expensive as the word custom sometimes implies.

We have a good spring shop locally, General Spring of KC, who custom build springs for trucks, cars and industrial applications. If you can find a comparable shop they will weigh your four corners, assess the needs as DaveS pointed out, and wind you some new springs to fit.

Agree with Uncle Bob. Get all your weight in the car (people and baggage) and weigh the RR and LR, then call Eaton.

Of course you will need to know the effective leverage depending on where the spring is mounted and also the vertical angle----------too many of these ride issues come because people just assume that the corner weight is the answer to the problem------