I just recived my rear view mirror from Chevs of the 40's the other day. I got the $60 985994 night and day mirror and it fit in my header panel with no problem, plus there it dosn't block any of your windshield view . I am sure that the $28 516506 would fit just as well. This is installed in my 46 but I also own a 40 GMC and the header panel is identical. I will take a picture If you would like to see.
Stuart
