Super Stock Springs and info needed !!!

Greetings - just obtained a 66 Dart and need to install Correct Super stock springs and off set hangers if needed to accommodate the following size tire [ 29.50 x 7"] slick to be used for Super Stock class racing . I currently have a 8.75 rear-end with drum brakes and was told it was out of a 70 Duster thanks for any advice etc , PS was looking today and the stock springs are almost flat they could be used to make some nice knifes .