I searched and didnt find anything too relevant . Here is the problem .
This is on the wifes 1995 Z28 . The car wont overheat right away it takes
about 10-20 mins of steady driving to do so . The car is now starting
to chug and act like it has a miss pretty badly . This is what ive done
to narrow down what the problem might be ....

New 160 Thermostat
New CSR Electric water pump
New Radiator
New Radiator cap
Manual fan switch on at all times
Pressure tested cooling system with car off and no leaks
No collapsed hoses
Car just started smoking white on startup but goes away

Im leaning towards head gasket but im really hoping not Any suggestions ???

 

If you are suspecting head gasket, read the plugs. Test the cooling system for exhaust gases.

 

White smoke is coolant so I bet you're right. It is obviously getting in the combustion chamber a little at a time and probably why it takes a while for it to overheat instead of it doing it right away.

 

How do I test the coolant for exhaust gasses ???