is the fan supposed to kicked on at 3/4 of the temp gauge i have a 94 Z28 with 96 LT1 engine

 

The middle of your gauge is ~212*F. The first fan (or low speed in "late" 94's and up) turns on at 226*F, and the second fan (or high speed) turns on at 235*F. The gauge reads the temperature sensor in the driver's side head. The PCM uses the temperature sensor in the water pump housing to control the fans.

 

is car running hot?, my two fans kick on at 3/4 of the temp gauge and it goes like almost to the middle when it cools down and when i turn the car off i dont hear any boiling so are my fans good

 

The dash temp gauge and the PCM feed come from two different temperature sensors. Its possible that one of the sensors is not providing the correct readings. Put a scanner on the PCM and see what temps the fans are going on and off at, according to the PCM temp sensor.

The center of the gauge is about 210*F. With the stock thermostat and stock fan programming, its normal for the engine to run with the needle in the center of the guage.

 

That is the way my car has worked since new. Without the A/C on the fans cycle on and off and the temp gauge swings up and down about like you have described. With the A/C on the temp stays steady since the fans run all the time. On the highway or with the A/C on the temp runs just above the 1/4 mark.