rear springs

Hello
My car (Saxon V6) is very very high from the back. I have almost 5 inches between the tire and the rear wing arch. I think my coil springs are too long or too hard for the weight of the car. Apparently the mounting is very similar to mounting the MX with a shock absorber at the rear of the wheel center.
So I'm looking for shorter or more flexible springs to lower the car, knowing that in France the choice for American cars is very limited, there is little choice.
I did not find on the forum of answer useful for me.
Do you have an idea of a car that could be suitable?
Thanks

It is possible to just shorten the springs by cutting a part of a coil off with a metal cutting saw. Perhaps this would make the ride height acceptable?

it's indeed a solution but I do not have much confidence and it will be in last solution. I would prefer to find shorter ones.

Keep in mind that cutting a coil spring in effect also increases it's spring rate and may increase harshness. Coil overs are fairly easy to fit to the rear on the Healey. There are a variety of spring rates and free lengths to choose from and are of course provide height adjustment by spinning the lower spring seat nuts.

If the car is still "as built", the Saxon used Chevrolet Chevette front and rear suspension. So any spring modifications would have to take that into consideration.

This car is factory built, and it have only 1500 miles !! i think it's full stock.

First, you need to know the spring rate of your existing springs.  To get an accurate measurement, you would need to pull a spring off your car.  You need to know the OD of the spring, wire diameter, number of active coils and the free length (unloaded length).  There are online calculators that allow you to plug in the numbers and come up with a rate.  In the US,  this will be pounds required to compress the spring 1 inch.  I'm not sure about the metric designation, probably kilos per centimeter.

Also, measure the compressed height of your existing springs. This will tell you just how far the spring is compressed from it's uninstalled height.

You will also need the rear sprung weight of the car.  This will be just the weight that is supported by the springs, not the weight of the axle assembly.

You could spend a lot of time, effort and money searching salvage yards looking a set of springs that will do what you want to.  I would suggest that you go to a spring supplier with the spring rate and discuss what you want.  

Without an answer from a Saxon owner that has actually done this, you will be on your own to figure it out.  Unfortunately, Sebrings seem to be much more common that Saxons.  I'm sure that a Sebring owner has an answer as it relates to Sebrings, but the Chevette rear suspension on the Saxon makes that info useless, except for an approximation.

I can tell you that the rear weight of a Sebring is about 1200 pounds and the axle assembly will weigh 150 to 200 lbs.  A rough approximation of sprung weight would be 1000 lbs.  Keep in mind that these numbers are of the top of my head and not actual measurements and I would think the Saxon is a little lighter.

Here is what I came up with on my Sebring MX just for comparison, Saxon results will vary.

OE Data Front:
Wire gauge 17/32"
OD 4 9/16" ID 3 1/2"
Unloaded free length 11 1/2" Loaded in car 8 1/8"
Static Compression 3.375"
Mechanical Advantage-2:1 (halving the spring rate @ wheel, 2" vertical movement of wheel results in 1" compression of spring).
Sprung weight average 550 lbs/wheel
Un-sprung weight average 103 lbs/wheel
Spring rate approx 300 lbs/inch (150 @ wheel)

OE Data Rear:
Wire gauge .50"
OD 4.75" ID 3.75"
Unloaded length 13" Loaded 8 1/2"
Static deflection about 4.125"
Mechanical advantage 1:1
Sprung weight ave. 450 lbs/wheel
Un-sprung weight average 150 lbs/wheel
Spring rate calculations were inconclusive

Viking Coil over data:
Front spring rate 175 lbs/inch, free length of 13"
Rear spring rate 110 lbs/inch, free length 12"
Shocks are double adjustable

my springs are 12 cm diameter, the wire is 13mm in diameter. The unloaded length is 32 cm