'72 GMC I6 to V8, motor won't stay running, wiring issue?

[grancuda]

I just swapped out my 250 I6 to have a 350 V8 w/HEI. I got if fired up but it only stays running for a couple of seconds and I am curious if some of the factory wiring needs to be connected to something. Originally there were 2 wires running to a solenoid on the carb, 1 wire running to the idle solenoid on the carb, 1 wire running to a temp sensor on the head and 1 wire running to a temp sensor on the lower part of the thermostat housing. Do any of these need to be connected to something for the motor to run? I am running an aftermarket gauge for the temp so I really don't need the temp one but didn't know if the temp sensor under the thermostat needed to be grounded out possibly. pretty much just cut the wires off and taped them up. For the HEI wiring I removed the yellow from the starter soleinoid, cut the pink wire where it comes out of the bulk head about 1" from the bulk head and soldered a new heavy gauge wire to it and ran it to the batt term. The truck will start but dies imediately. I am thinking it may be one of the engine wires but don't know for sure.