Painless wire, temp gauge help

[GMC3]

I have a painless wiring kit I installed on my truck. Replaced temp gauge that was not working. I have 2 wires in the kit for temperature. One is for the gauge and one is for the lights. Do I need both or just the one for the gauge. Also I have a 350 w/ vortec heads and edelbrock performer rpm intake. the rad hose covers inlet in intake for sending unit and the threads for the stock 1970 are too big for the vortec heads any info on how to hook this up would be helpful. also where can i get the plug that goes into the sending unit to hook up to my wire from painless

[GMC3]

OK. I think I've got it. grounded the wire to the gauge and it pegged. grounded the wire for the idiot light and it came on. so I do need both wires and both the temp sending unit and temp sending switch. Also took a better look at my intake and there are inlets on both sides of the carb that should work. the wire hook up for the idiot light switch is no problem b/c it is a quick connect. but don't know how I'm going to hook wire up to temp. sending unit. any one know where i can get that. not much in bone yards up here any more. and looked in LMC catalog and didn't see it.

[hemihead]

I hooked up my sending unit by utilizing a crimp on end (fork type I think), soldering and heat shrinking it to the sending unit. Been on all summer with no issues