well how? hehe

 

Look at the car they came out of?

Doesn't matter, they're all worn out after all these years.

 

Although the spring rates are probably all worn out the only way to "kinda" tell is by measuring the thickness of the wire. Thin wire will have a lower spring rate for a lighter car. Thicker wire will have a higher spring rate for a heavier car or for stiffer suspension such as IROC or WS6 suspension.

It's not so much V6 or V8 springs but how much the spring rate is. I use front springs from a V6 car in my race car. Since I have so much weight removed from the front end, the car still sits high.

What you need to do is drive the car onto a scale. Drive the front wheels on to about the middle. That will give you a weight on the front. With only the rear wheels on the scale will give the rear. Add the 2 together and it will equal the total. Once you know the front weight you can get springs matched for that weight.