I have the same issue. The fuel is getting too hot. Use a carb spacer that will insulate - and block off the crossover directly beneath the carb if possible.
Coolant temp sensor ... dr side lower block.
First wires you asked about should connect to O drive disconnect vacuum switch. Previous poster showed it in a pic. Dr side firewall next to booster. It disconnects the o drive when under low vac.
I have an 82 k10 in the same state. Took me 2...