guys i find myself in a dilema. i am restoring my 67 ss 396 vert, and am finishing up the frame. i am using the original springs as of now because i liked the ride height. the problem i have is the rear spring look different than any other chevelle i have done. they look similar to the front coil springs only smaller in diameter. they are the same size from top to the bottom coil. i have a part number if anyone can tell me what there for. p587805b is stamped into the spring. also is there a book out there i can buy to decode this stuff? thanx