Looking for correct front strut bar hardware (serrated washers and front and back nuts) for 67 Shelby.
Assuming that this is for a regular production Mustang, you should check this forum's library under topic "Mustang Hardware Spreadsheet 67-68". You will find two spreadsheet files, one by Ford part number, MHW67-68PN06.xlsx, the other by use (application), MHW67-68AP06.xlsx (the "06" is the revision in both files). These files were based on the Mustang Assembly Manuals, Ford Car Parts (aka MPC, for service numbers), and other sources.
If you do not have a set of the 67 Mustang Assembly Manuals, I recommend you get a set.
Jim