413 overheating or bad gage?

Ok, so I was FINALLY able to find the correct temperature sending unit for my 1964 300k with 413/w AC. BTW this motor only has 1 port for the sender(which SUCKS). However, I got the new one installed and hooked up a "equus" aftermarket electric temp gage.

I go to crank the car(it hasn't been ran in a week or so, so definitely cold) and it jumps straight to 160-180 degrees according to the gage. After it idles and drives about a quarter mile it hits 240, however it doesn't feel like its...

413 overheating or bad gage?