XV Motorsports did a chassis evaluation and spring rate calculations on a stock Cuda. After the test, XV recommended to soften the rear rates, and firm up the front spring rates to achieve a balanced car. Originally, the cars were too stiff in the rear and too soft in the front. I have the XV Level 1 torsion bars and rear leafs. My car is much much more composed and balanced. No harsh rear thumping and no bottoming out of the front over large bumps. Just something to think about if you are researching rear spring rates. You can find videos of this on youtube. Sorry I don't have a link.
Here is a warning. Once you start making significant changes, each new piece leads to shortcoming of whatever hasn't been changed. You will end up replacing everything once you start getting it riding and steering nice. If you know now that you want your end result to be a modern feeling car, start with the subframe connectors. A stiff chassis if the basis of all the suspension settings. If you only want a small improvement and still want the old car feel, start with quality shocks (bilstein, fox). Start saving now!
