Gauge question

[SS317]

I have the original instrument cluster in my truck. I have an aftermarket Chevy 350 in my truck. Right now I don't see the needle move at all for temperature. It's about 1/3 of the way over and stays there. If I get the temp probe that is suppose to be on the original engine, wouldn't it work the same on the 350? I don't think whoever installed the engine ever hooked it up. The only gauge that works is the engine oil pressure, it seems to be reading accurate. I can get one at the local NAPA for 6 or 7 bucks.

My fuel gauge is on E all the time. I'm going to check all my grounds and pull the sender from the tank tomorrow to see what I have, and ring the wires to make sure they are correct.