318 Overheating...Help!!

Hi Everyone. Im about to go insane. I have changed everything I could possibly think of and am now on the last thing it could possibly be but before I spend anymore money, I decided I'd check with all the folks on here.

Like I said, after spending $600+ on changing the radiator, water pump, thermostat, hoses, radiator cap and temp switch, I've narrowed it down to the actual gauge.

The gauge reads 210 when its nice and warm but I dont believe thats correct.

So my question to you guys is..

What else could possibly be causing it to overheat... if it really is?

It has never overflowed or spewed coolant. I have also ran it with the cap off and I can see the coolant flowing.

Any thoughts are greatly appreciated... I dont want to dish out another 70 to 100 bucks on an autometer gauge if thats not the problem. THanks!

oh and the oil looks good too and there is no splatter out of the tail pipes... no more than the usual condensation.

THANKS!