My friend finally found the problem!!!!!!! but gained another one.
The GTA would heat up to 100 degress then shut off, it turns out the fuel injector was not at the right ohms and the switch in timing shut down the rest of them like a christmas tree!!!!
SO he replaced the injectors with a Y84 injector,,,,for his 305 tpi.
Now it back fires and pops and runs like a bag of poo. ARe the Y84 injectors the right ones for a 305 TPI?