Steering coupler

That is correct. The Valiant was the Barracuda in all aspects except the front grill and rear window. There were running changes on how the thing was held on: bolt, roll pin, allen set screw....The thing is to get the shoes in for minimal/no play. Her eis a great write up including the 13/16 measurement from 'witness mark'
Rebuilding a 1964 Plymouth Steering Coupler