Well, I've been putting off this anouncement but here goes:
I HAVE THE ONLY ACCURATE 122 WAGON SPEEDO IN THE WHOLE WIDE WORLD!
How? A LOT of cobbling. I have taken a speedo face that only reads up to 100mph(no, I don't know what it came out of, probably a real early car) and installed it on the front of a 120mph assembly. I had to ream out the holes for the idiot lights to get the insulators to seat so light would not bleed through. The lines on the reel tend to vary from the numbers (120mph reel behind a 100mph face) but if I concentrate on the ribbon in relation to the numbers only (ignoring the lines on the reel), it seems to be real accurate.
Before installing this particular unit (I knew it would be right, I had it in my other wagon years ago), I experimented with several other clusters (undo speedo cable and hook it up to another cluster on the floor-read it on the way to work). None of these were consistent and all read high. Final experiment was to alter spring tension-there is not much stretch there to play with or make a much of a difference IMHO-FWIW.
Helpful hint:If your dash cap is not glued on, the cluster comes out the top much easier.
LUCK!
Shayne
'64 220, '66 130, '76 124CS