What were the stock and GT/GT350 coil springs rated at in 68?
I'm thinking of going to a lighter spring and roller perches. Maaaybe progressive springs, but I don't like the idea of the transition point moving when I use aluminum heads.
it seems like the springs you have would work fine. why not try the roller perches with what you've got? you are right about the front end lifting with less weight, though. I took off about 130 pounds off of the front, and my car is about 1" higher than it used to be.