I found detailed information on 9 inch axle pinion snubbers done by Anghel Restorations.
https://anghelrestorations.com/wp-content/uploads/2021/09/pinion_snubber_v1.0.pdf Our thanks to Anghel restorations for the research done on this. With the various designs that evolved I am wondering if the bracket was getting bent or damaged in use.
Ford Product Development determined that pinion snubbers were needed when an axle and driveshaft went into full jounce to minimize the sharp jolt (thump) a customer would experience and to prevent the driveshaft from hitting the tunnel and damaging it. On a new car design or an increase in driveshaft diameter we had to do a vehicle test for clearance. To worst case the test we would remove the rubber bumper and put 400 lbs in the trunk and then use the test track to achieve full jounce