With the RH passenger door mirrors now available, there will be many looking to install one on their 1963 or 1964 Cadillac. A template aligned with the edges of your door, showing the exact location of the 3 holes would be ideal, however, I thought I would share the specs on the holes you will need to install your mirror since my 1964 Coupe de Ville came with the rare dealer installed RH mirror.
FIRST: I recommend removing your LH mirror. To remove you simply loosen the Allen screw in mirror control handle and remove the retaining screw at front top of the door. Slide mirror back and it will lift up and off the door. You will be left with an excellent template for the RH door mirror. The only difference will be you will not need the larger center mounting hole on the RH mirror. See below for details.
There are many ways to make measurements of the 3 holes on the top, however, this is what I did:
1) I measured from top door ridge up to bottom of mirror hole. Since the mirror holes are basically parallel to the top door ridge, each measured 3 71/6" from the ridge line.
2) I measured from front door edge back to the forward edge of the hole. Measurements were 2 3/16", 3 11/16", and 5 3/16" starting at front hole.
3) I measured diameter of the hole. They are 3/4" in diameter. Note on the LH door more the center hold is 7/8" in diameter due to the center control rod. Since the RH mirror does not have the control rod, you only need a smaller hole for the mirror arm base attachment, and only need a 3/4" hole.
- Attaching Screw Hole in front top of Door. Look at your LH door front top where attaching bolt goes. The RH door mirror attaching screw goes in same location on the RH door. There is a roundish area where the screw hole needs to be drilled. Drill a 3/8" hole in the very center of the round attaching area. (Note from the factory, I get measurements of 7/16" but do not believe it needs to be that big... just enough to move the screw around to find the thread in the base of the drill.
- LH Driver Door Mirror Comparison. For a sanity check, I compared all measurements above to LH core doors I have on and all measurements were consistent with and approximate to the RH mirror hole specs above.
I hope that helps in the installation of your RH mirror! Below are pictures I took that go along with the description above: