Egr valve ? hei module ? Carburetor ?

The thermal switch turns on the EGR when it is cold. It has to do with the timing and air fuel ratio. Because an engine takes in more fuel and air when it is cold you can advance the timing with out detination. You also need more fuel to keep a proper air/fuel ratio since cold air is denser. If you can get rid of the thermal switch, vacuum advance, the TVS and the EGR and get a non-advancing distrbutor for it and set the timing and air/fuel ratios right from the beginning then your problems should go away. You can get an A/F.R gauge at say Advance Auto Parts to set the ratio. Set your timing first then keep switchig between them until your stoic AFR is 12.5:1 or so and you have no pre-detination or delayed knock.