40 some years ago a shop made a 1/4 inch thick ring that they press fitted over the 7 1/4 hub and then stitch welded it to the hub.
They then heated the hub up very warn but not hot and TIG welded the 5 ea 7/16 stud bolt holes up using a copper backer plate behind the weld.
Then they redrilled and tapped them for 1/2 inch screw in studs on the LBP.
That car had 4.10:1 Suregrip and we ran G60 15's for years.

I also have a set of 1974 Dart Swinger LBP 7 1/4 axles somewhere out in the garage. But not sure its a easy swap. Wheel bearings or splines may be different.