Hey Jason.
If yours indicators have the screw that goes in from the top they are just sheet metal screws with a tapered seat and slight oval head.
I can get you the measurements off my car in a bit here.
There is going to be two holes for each light. (one for the screw and one for the wire)
The other type (like the Wife's 72 Swinger) have one hole in the fender and a nut that goes on from the underside of the fender.
Ok, the type that has the screw in the top holding it to the fender.
6-5/16 back from the front of the fender metal itself.
2-7/16 from the center of the ridge on the outer edge of the fender.
That's where the screw holes are, so the wire hole you can figure out from there.
I would suggest to get a chrome or stainless screw that fits the indicator nicely first, then drill your hole for that screw.
The important part of those screws is the head and how it fits the indicator itself.
What thread type is not as important.
Also note that they get their ground through the fender metal, so you may have to scrape a bit of paint off where the copper contacts on the bottom of the fixtures meet the fender.
