I followed the instructions in this link http://www.persh.org/pickup/interiors.htm#tachometer you can get the tach from JCwhitney, very easy to do
Just saw your pics of the cheap-o tach. Was considering a similar application on by 64 C-30. Wondering how hard it was and what all you had to do to make it look as good as it does. Thanks 1964ChevyC-30