<VV> What puked?

[judynrandy at comcast.net]

When fixing up "Rusty Frankenvair" (my '60 4dr) for duty as my winter daily driver, I installed a Spyder dash along with a '64' 110 with headers and a 4spd.  All was well and it ran like a champ.  Then the tach puked.  I replaced it with one from the Corvair Ranch, but it was d.o.a. and never worked.  Oh well, at least the temp gauge and thermistor worked fine.  The car cruised at around 300 degrees with the cooling ring up, and 325 with it down. (I used a '60 block and cooling system)  Until now.  Today, as I drove merrily along, the needle went straight to 600 degrees and stayed there.  Then, after leaving my destination to head home, it stayed at the 200 degree mark for a minute or two, then jumped to 400, then in another minute or two pegged at 600 again.  When shutting it off, the needle returns to 200.  Does this mean the thermistor puked? Or is it the gauge?  Also, does anyone know of anywhere I might be able to get the tach fixed?  Thanx for your input. 
  
Randy (Cap'n) Hook 
'60 700 4dr '64'110/4spd 
'63 ragtop 110/4spd 
'65 Monza 4dr 84/pg