Fired up my 400sbc - Question about temp gauge

[Yukon Jack]

Fired up my 70 K5's rebuilt 400 sbc for the first time this weekend!

Here is an audio clip of the motor MP3 file

Here's a pic of the motor



Ran great but the temp gauge showed it was running a bit on the hot side. I'm pretty sure the gauge is not accurate - I bought the K5 and it hasn't been running since I bought it.

I have a spare bezel and was wondering if I could run a wire from the sending unit to this spare, uninstalled bezel to see what it shows for the temperature? I looked at back of the bezel and there are four posts - could I attach the wire to the correct post and get a reading - if so, anyone know which post should be used?

I did pick up a generic O'Reilly's temp gauge and hooked it to the sending unit but it didn't work - I'm guessing the generic temp gauge's sending unit must be different than the GM sending unit I have installed.