Overheating mystery????

[jlane1820]

Here's a follow-up on my previous post on the temp switch wire. I finally located it, it was tucked away underneath the truck near the transmission, covered in oil. I cleaned it off and hooked it up to my temp switch and now I have a working temp gauge!
But...
Now when I start it and warm it up, the gauge tells me I am overheating. Everything seems to be working as it should, and I really don't see any visual indications the truck is getting hot. My radiator stays full to the neck, no white smoke indicating a head gasket leak, the coolant seems to be circulating when I look into the radiator, which tells me the water pump is working, and no coolant leaks anywhere else. Going by my sense of feel, the engine doesn't even seem much hotter than usual. So I am stumped 
The latest work I've done is add an Edelbrock manifold and cam (just the Performer, not too aggressive). I adjusted the valves so the oil may be a bit low, but would that cause such an extreme jump in temperature? I've advanced the timing a little too. I also put a new 180° thermostat in the new intake and put in a new temp switch. Is it possible the new switch is giving a false reading? Are there more than one type of switch for these? Could it be the stat perhaps? Any suggestions as to what may be causing this would be appreciated!

[Captkaos]

You may need to replace the sensor in the head with a new one.

[jlane1820]

That's the thing, I put a new one in once I found the wire. I did notice my old sensor had the 'knob' type connector whereas the new one I got has a blade connector. Could these be different to the point where they give different readings?

[Captkaos]

You need a sensor specific to the year truck/gauge style.

[jlane1820]

Apparently, that's what I was given when I bought it. I mean there were only 2 options, the sensor for trucks with a light, and one for trucks with a gauge (which would be mine), both of them have a blade connector. The old sensor I took off has like a metal button 'knob' connector in the center, it fits the connector, but so does the blade on the new one (the temp wire connector is a blade connector with a slot in the plastic insulation to connect to the button). Apparently no new sensor has this button connector, they are all blades, unless I am missing something??
Let me ask this...given the old sensor has a button connector, centered in the sensor, giving it some room between it and the exhaust manifold. With the new sensor, screwed in to exact torque specs, the blade connector is about 1 o'clock, closer to the #3 exhaust port of the manifold. Could the connection being this much closer to the manifold give it a false reading?
I really appreciate your help on this CaptKaos, but it's still just not adding up Have you or anyone else had similar experiences with a new sensor?