According to the GM book, the spring rate for my '66 Chevelle is 320 for the fronts, (120 in rear). I wanted to lower the front by 1-2 inches, (will be putting in a 396 engine).

Not sure what spring rate to ask for, or if they even sell them according to this number. And what is the difference between SB and BB? All help very much appreciated by a novice restorer.