[Healeys] wire harness fasteners

[mailmaineguide.com]

Hello List, I am routing the rear wiring harness along the inside of the left
frame member as instructed, however the holes drilled into the frame to hold
the "P" clips are about 5/16" in diameter which seems way to large to hold a
standard screw, is there an insert of some kind that goes into the hole first?
I can find no reference to any in the parts or service manuals. Thanks again.

Brad Holden
67 BJ8