From 1967 through 1972, low-back Mustang bucket seats were a special-order option from Ford for F100 thru F350 trucks. These seats utilized specially-designed mounting brackets which have been extremely hard to find.

However, I was able to get my hands on a full set of these brackets and hired a professional CAD artist to create some detailed schematics which could be used to fabricate these brackets for use in your own truck. These images are shown below in either .jpg format, as PDF files or as a .zip file which includes the raw .dwg files which can be opened in AutoCAD or SolidWorks.

The jpg images shown here are just for quick online reference. To view in higher detail, download the PDF files. Also, since the brackets are mirror-images of each other (driver's-side vs. passenger-side), only one CAD schematic is shown for each bracket. However, the dimensions are the same, they'd simply be reversed to do the opposite side.