[Benjamin]

I am very interested in this topic as I plan to perform the same upgrade in the near future.

This article may or may not be helpful for your specific application.

http://www.fourwheeler.com/how-to/tr...ower-steering/

The 1970 Suburban in this article apparently had a relief stamped in the frame, but the writer did mention that not all manual steering frames have this and that you may need to fabricate a piece to compensate.

Is it possible that in 1968 the frame was flat for manual steering applications, but by 1970 the relief had been added to the frame, regardless of whether the truck was equipped with power steering?