I am a little experienced in wiring and guages. Is it possible to hook two temperature gauges to the same sender? I tried it and it doesn't seem to work. I have the original dash factory guage in a 66 hooked to the temp sending unit that screws into the intake. I just mounted another gauge and hooked it up to the same sender. Should this work? It doesn't seem to work correctly. What could I have done wrong? Any suggestions?

What I want to do is see what the actual temperature is and where that measures on the original guage. Would also like to find how the original oil guage reads. Thanks.

Arrange a switch so you can switch either gauge into the circuit and the other gauge out. Can't run both off the sender simultaneoulsly. Unlikely that s factory gauge and an aftermarket would both indicate accurately from the same sender. Senders and indicators are matched elctrically. Pretty much have to use a brand X sender with a Brand X instrment and so on...My $0.02

Could you run a sender into the cyl head port? I run a temp gauge sender, and a separate switch for the electric fan. Since you'll probably have another sender, it's just a matter of taking the plug out and putting the sender in.