I'm trying to sort out some handling issues on my 1971 Satellite 4-door police car clone. I've tried to make a decent-driving car, within the constraints of 15-inch tires. Here's what I've got in a nutshell:

FRONT:
1.03" T-bars
Suspension rebuilt with Moog hard parts
Firm Feel upper control arms
Steering box from Firm Feel
Polyurethane LCA bushings
Helwig anti sway bar. I think it's 1-1/8, it's been a while since I installed it and the memory fades
Koni shocks
225-70-R15 Cooper Cobra tires (being a police car clone, I'm stuck with 15" wheels)
Alignment is 1/2 degree negative camber, 5 degrees positive caster, and I do not remember where the toe-in is set.


REAR:
6-leaf Mopar Performance springs, intended for the left side of late-60's 440 & Hemi B-bodies. I can get the part number if needed.
Helwig 3-way adjustable anti sway bar. I think it's 3/4, it's been a while since I installed it and the memory fades
Koni shocks
235-70-R15 Cooper Cobra tires (being a police car clone, I'm stuck with 15" wheels)

The problem is when driving on a straight road with slight dips in the pavement, the rear end is "bouncy" for lack of a better term. Constant, tiny up-and-down movement. Harsh dips are handled much more effectively and satisfactorily than tiny ones. I've cranked the Konis from one extreme to the other with many stops in between, and the problem cannot be rectified. So yesterday, I pulled the QA-1 double adjustable shocks off another car and put them on the Satellite and will see if they can help the problem.

A FEW OBSERVATIONS AND QUESTIONS:

The rear springs give the impression that they are too stiff. I have removed one and two leaves for trial. That seems to help but the car squats too low in the rear. I'm confused though, as these same springs were factory-installed on 60's cars with bias ply tires. Wouldn't radials want more, not less spring rate? BTW, I have removed the U-bolts and checked that both saddles sit squarely on the spring perches... I understand that if the rear end were in a bind here, similar symptoms would occur. I could just remove two leaves and get the springs re-arched (or buy different springs) but I'm somewhat surprised that these springs exhibit the symptoms I'm seeing.

Compressing the rear suspension by pushing the rear bumper down causes the tires to visibly compress. I've tried 25 to 38 pounds of air in them... it seems to be happier with less inflation. The fact that the tires compress and not the springs also seems to indicate too-stiff rear springs.

I have the QA-1 shocks on now and I'm thinking of trying a low number on the compression damping and a high number on the rebound damping, which would seem to make sense if springs are too stiff.



I'm way past my knowledge and experience in this area, so any advice is appreciated.

Jim