I am using the stock leaf springs in the '72 Duster and have a pre '68-'70 8 3/4" for it. The perches have been cut off and new ones ready to install. Am I safe expecting with stock springs where the perches sit to be parallel with the bottom of the car? So can I safely align the perches with a -8 degree (with respect to 90 degrees) or so angle to the face of where the center chunk bolts to and have it come out fairly close to -8 degrees when all together? I don't have the K-frame and power train in the car yet and would like to get the rear axle done before that happens. Thanks.