This is a comparison of the three kinds of hood louvers that I considered installing in my Merkur.  The left ones are cosworth replica hood louvers. The middle pair are from a 1992 Pontiac Gran Prix Turbo.  One is black and the other blue.  These were purchased from two different cars that were located using www.mypartsshop.com.  These are the louvers that I have drooled over since the Gran Prix Turbo came out.  The right hand set are from a Pontiac GTP.  These were purchased from a list member.

The next photo shows roughly where they will be installed into my hood .
I used a piece of cardboard and made a template by inking the mounting pegs on the back of the louvers with an ink pad, then pressing it on some cardboard.  I then used it to drill into the hood and then flipped it over and did the other side.  I lined up a template that I had made of the necessary cutout on these drilled holes and drew the cutout on the hood.  This way, they were exactly symmetical.  I then used a dremel tool and about 65 of the little cutting discs to very carefully cut out this hole. 

 
 
 

I will post photos of the finished install when they are done.  The mesh screen above is a screen between the louver (above the hood) and the rainguard (below the hood.)  Because of the great size of the louvers, I DID have to cut some of the reinforcement behind the hood.  I will have the body shop weld in a piece of sheet metal to the hood to restore the original strength.