F600 Mechanical Tachometer Replacement

I thought I would single out this topic for the pure joy of finding a tachometer that actually fits the F600 mechanical tachometer hole size.  Any of you how have tried to accomplish this knows that most tachs are 3 3/8" diameter and that doesn't fill the almost 4" hole the old tach left behind.  Then there is trying to finding something that looks close to original is almost impossible.

I pursued all angles:

1.  Rebuild the original.  I found two companies that would put new guts and a new face to match the original, but both were over $400.  I don't mind putting money into something but there is that part of me that considers the amount of return 400 plus dollars would give back and I wasn't seeing it.

2.   Try a smaller size diameter and spend less money.  I then went  to another option and used a $100 tach that was 3 3/4" and had a friend of mine laser cut some rings to fill the gap and it looked pretty good.  The problem was that the tach didn't like good ol' ford genuine parts and wouldn't work.

3.  Spend a little more money for the right size.  I started researching again and on my first search found the tach that would fit.  I don't recall finding this the first time I sought out a tach but maybe I did and just didn't like the $169 price tag.  That price seems insignificant now that I spent a total of 2 working days trying to get the $100 tach to work.

The Auto Meter Cobra Tach Is a 4" diameter and has a bezel that matches the rest of the gauges and takes 10 minutes to install

I didn't realize how grubby my panel was until I saw this pic.