Upgrading a 1969 Roadrunner with my father. Very excited to get this done, but needing some guidance on a few different aspects. Any information will be useful. We are looking to go from manual to power steering and we're looking for a 5/8" 35 spline (NOT 36, it will not fit) x 3/4" DD U-Joint for the power steering gear box. Please give any information that you may have or any guidance in getting this completed!