Temp gauge magnum block

What intake manifold?
RPM?
On the center behind the thermostat (not directly shine it, just off to the right) there is a small hole that I drilled larger for a temp gauge sender. You can still use the stock sender in the intake about where it is normally placed.
I think thats where i relocated heater hose. This a magnum engine and i'm going to use a/c which kills using hole underneath compressor.