I believe it was Corey who had asked about this. I am going to post in 67 thread as well.
This is the Ford Sevice manual instructions as well as the tool that must be made to do so.
The tool is made with .250 "piano" wire. You can find this in Hobby Shops. The straight portion is about 4" long and the 45-degree bend is about three inches in length. Be sure to clean up the edges of the end that you cut. You don't want it longer because it will hit the driveshaft tunnel and you may not be able to get it in the hole.
Be sure it passes through ALL three levers before you start trying to make adjustments.
A 1/4" drill bit works too.
If it's short enough to clear the tunnel. Big blocks have less room than small because of the cross member difference. That tool is made from a Ford spec sheet.