None of these conversions are quick, easy, or cheap. Nothing that I am aware of is a direct "bolt on". If you are looking for a Saginaw box the truck boxes mount outside the frame and are used on trucks from 67-87. The car boxes mount inside the frame on approximately the same years. Both have a standard ratio and a quick ratio available. There is also a 605 steering box used on late 70's mid 80's mid size GM cars. You will need to fabricate and/or purchase the related steering components for your application.
Fred
