Just repainted my 70 GMC stepside and bought new 3 hole mirrors and gaskets for both the driver's and passenger's side doors. My question is how does one get the backing plate inside the door aligned so that the gasket and mirror can be screwed to it-- I'm guessing it has something to do with EXTRA long arms- and the help of another person... but if there are any secrets out there I'd sure like to hear them.
These are the type mirrors I'm talking about- second section down on the left side of the page.
http://www.lmctruck.com/icatalog/cb/865w/0077.jpg