Ok replaced my HeadLight switch did not correct this problem, When I turn my headlights on seems that with
the dash lights illuminated the guages all shut down, The gas guage goes to empty, the tach goes past redline and stays, the amp guage functions only. This car has the
ECM removed as it is now a Carb 350 engine. any thoughts
or things to try ?...Checked all the grounds and all good.

 

It's a pretty common problem mine is doing it too.... You might want to take the gauges out and look for breaks in the Printed Circuit Board on the back.

 

Had that out and all are looking good, even tried another
guage cluster, same thing.....

 

dangit I just bought a new cluster off ebay....

 

right now I tend to think that by the Sirs system using the guages fuses as well as thier own it might be a overdraw on
the headlight switch causing a power drop but will test
further and see where that leads too..

 

TTT Anyone have thoughts ????