Stock gauges mechanical vs electric ?

[TJ Hopland]

Now that I am working a bit on my dad's 57 I am looking closer at other 50's era cars and looking at the differences in them.   One thing I noticed is that some of the 50's gauges are electric and others mechanical.   Wondering why?   Like to have a mechanical oil pressure gauge and an electric coolant temp on the same car?   Was it a cost thing?  Reliability?  It seems that the technology to do either was proven by the 50's.  I can see electric being easier on the assembly side since a wire is easier to deal with than a capillary tube for a temp gauge or tube for the oil sender. 

[bcroe]

Now that I am working a bit on my dad's 57 I am looking closer at other 50's era cars and looking at the differences in them.   One thing I noticed is that some of the 50's gauges are electric and others mechanical.   Wondering why?   Like to have a mechanical oil pressure gauge and an electric coolant temp on the same car?   Was it a cost thing?  Reliability?  It seems that the technology to do either was proven by the 50's.  I can see electric being easier on the assembly side since a wire is easier to deal with than a capillary tube for a temp gauge or tube for the oil sender.   

I like the capillary tube temp gauge; saw a post how to rejuvenate them recently.  Don't
like them on oil pressure since a break could run your engine out of oil, or even dump it
inside the car.  Some 57 Cads used an oil pressure and a tank gauge built like a 3 phase
syncronous motor.  The sender had a ring of resistors with battery applied to sliders on
opposite sides; 3 points on the ring went to the gauge.  These gauges survive, but the
sending units fall apart.  A while back a board was designed so a conventional, readily
available sender signal could be converted to run the original 3 phase gauges.  Bruce Roe