Getting the 440 cleaned, painted and ready to swap in the R/T Challenger.
I would like to try and use the factory ralley dash temperature guage and use aftermarket electric temp guage at first just to make sure everything is accurate.

The engine is a 1966 440 and it appears to have multiple ports for temp sensors in the water pump housing?

In the attached pic the port under(below) the thermostat was what I was using in the past with an Autometer temp guage, it's a bigger port with a reducer for the smaller temp pickup.
It has worked fine in the past.
There is also a port above the thermostat that the sensor fits in perfectly.
Will both these ports work?
Will one have a higher temp reading than the other because of it's location?

Thanks.

Any port in water will work. I wouldn't expect much difference in the reading within a couple inches of the T-stat.

i use 2 units on my r/t. one tells inlet temp, the other outlet temp.