QUOTE(dgraves @ Oct 13 2016, 08:09 AM)
I'm very raw with car wiring so please excuse any dumb question. What is the "main Loom"? Where exactly in the diagrams are you linking me to? I really appreciate the help.
The "main loom" is the thick snaky collection of wires that runs atop your center tunnel.
The oil temp wire should terminate somewhere around the shifter along with some other wires since the original temp gauge was in the center console.
The oil pressure wire should terminate somewhere behind the dash. The main loom splits into several smaller looms behind the dash.
So in short:
Look for a green/black wire near the shifter for the oil temp. It should have a plastic covered male connector on the end.
Look for a green/red wire somewhere behind the dash in the gauge cluster area for oil pressure.
NOTE:
The stock setup only had a oil pressure idiot light (green/red) which goes to the warning indicator on the gauge.
Hopefully the PO already ran a new wire for the oil pressure gauge and installed a dual sender on the engine.
You can use the '73 color diagrams in the link i posted, they should be the same as your '74 for the oil temp/pressure wiring and are much easier to read than the '74 current flow diagrams.
Look at the '73 part I and II diagrams and their respective legends.