1977 Pontiac Firebird Formula AC installation

[march23]

I recently acquired a numbers matching 1977 Pontiac Firebird Formula 400 4 speed with W72 performance package.  It has been completely restored, have original build sheet and PHS documentation.  One thing it did not come with from factory is AC.  I would like to have AC professionally installed such as Vintage AC but I also do not want to negatively impact the value of the car.  Any feedback on whether if I install AC professionally will impact value one way or the other.  Also, if doesn't hurt value, suggestions on how I should proceed?  What product or company would be best to utilize? 

[firebirdclub]

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