1 more to go! Got my tach working. It looks to be reading about 1/2 of what it should be. Have to look at the tune and make adjustments.
So last one is the fuel gauge. Here is what I know about this...

I read on LT1swap that on the LS PCM on C2 (Red Connector) you add a pin in slot 38 - ADD PIN FOR PWM FUEL GAUGE SIGNAL OUTPUT (used to run factory fuel level gauge in 96-99 trucks).

54 - is a Purple wire and named Fuel Level Sensor Signal


On the 4 connectors that went to the OLD Vortec PCM there are two wires that deal with fuel level. They are:

C3 (Clear) - PIN 13 is a Purple/White wire labeled Fuel Level Sensor Signal
C1 (Blue) - PIN 9 is a Purple wire labeled Fuel Level Output

Which of these wires are needed for my gauge to work? Thank you all for the help, looking forward to getting my last gauge working so that I can get rid of all these unused wires!