Thanks to all the responses I really do appreciate it. To answer to those who have responded. Yes the dexcool to water mix in the system is 50/50. The temp guage itself was my next thought as well. So I did replace that but still just as before the guage reads hot and upon a 7-8 mile drive all coolant is spraying out the overflow tube on the coolant tank. I do bleed the system correctly using the release valve,heater on while filling, and proper burping. So with the entire cooling system replaced. Replaced 2 thermostats,water pump,radiator,coolant tank,radiator cap,dexcool,hoses,temp switch. I will try the suggestion of the intake manifold gasket. Give me a chance to see what its lookin like inside.I guess. Any Other Thoughts Please?!

Hello Taz..might check the converter to make sure the exhaust system does not have excessive backpressure. Also make sure the electronic cooling fans are cycling...they should kick in and out. They are tied into the A/C system circuit with a relay.
The 3.1L and 3.4L V-6 Engine (VINs J, E - RPOs LG8, LA1) were known to have intake gasket failure. This was due to a bad gasket that was designed by GM...it had nylon in it...Over 400,000 of these were sold in Canada alone. The gasket has since been redesigned and torque specs recalculated. If you replace the manifold gaskets follow these guidelines.

Install a new design intake manifold gasket. The material used in the gasket has been changed in order to improve the sealing qualities of the gasket. When replacing the gasket, the intake manifold bolts must also be replaced and torqued to a revised specification. The new bolts will come with a pre-applied threadlocker on them.

Notice

An oil leak may result if the vertical bolts are not tightened before the diagonal bolts.


Diagonal bolts may require a crows foot to tighten.

Tighten

1. Tighten the vertical lower intake manifold bolts (1) to 7 N.m (62 lb in).

2. Tighten the diagonal lower intake manifold bolts (2) to 7 N.m (62 lb in).

3. Tighten the vertical lower intake manifold bolts (1) to 13 N.m (115 lb in).

4. Tighten the diagonal lower intake manifold bolts (2) to 25 N.m (18 lb ft).

Good luck...i hope this helps.

Previous respondents have all made good sense with their logical suggestions.
Here are a couple of 'outside chances'.

You may have already checked, but check that the coolant hose on the inlet side of the waterpump is not soft, causing it to collapse, restricting coolant flow when engine revs are running above idle.

I had a similar problem some years ago with a 350 chev motor- I too had installed 2 new thermostats (wax pellet type) without success. I took it to a radiator shop for radiator core and coolant gas checks etc again with no success. The mechanic suggested I install the lowest temperature thermostat (170 degC) for a try. I did and it fixed it. Counting the original, I had encountered 3 faulty thermostats! While this may not be your problem, I suggest you check one of the removed thermostats in a can of boiling water (use a cooking thermometer) to check that it opens correctly at the designated temperature.

Another similar overheating problem I encountered with an Alfa 1.8L Giulietta which overheated randomly. After all the checks were conducted to no avail, I took off the head to investigate further.
Found nothing but a ball of silicon sealant which had found its wayto the coolant thermostat header housing - it was too big to pass the thermostat, but apparently would occasional block the flow to make the engine overheat. Removed it, re-assembled motor - no more cooling problems. Moral - don't use too much sealant on gaskets or housings.

Best wishes