Scott Drake's mirror isn't a correct '71-73 style, it's not even correct as a 69-70. They say it's an exact reproduction of the 67-68 mirror, but then put it in their application engine as a 67-73. Consider it as a universal "fits all" type. It will work if you're not picky on the angle.
You can get the real deal D1ZZ mirror, but it'll cost you
https://www.ebay.com/itm/325454211597
https://www.holley.com/products/exterior/doors/door_mirrors/parts/C7AZ-17696-A
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ACP offers a correct 71-73 mirror, that is angled properly. However, this causes a problem if you want to install it on the passenger side. Ford didn't offer a passenger side rectangular chrome mirror for the 71-73s. If you wanted two mirrors, it was the racing style, or you made do with one from another car.
https://buyacp.com/parts/outside-mirror-driver-side-fm-bm006/
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