87 s10 instrument wiring and electrical help for new guy

[cdc3jj]

I'm doing a front clip/motor swap from a 87 s10 into a 52 chevy. Trying to build a "green-rod" that'll get great mileage and have low emmissions...

Ok, if you're still reading, and have stopped laughing here's the questions.

First, is there a diagram that outlines the wiring to the insturment panels? This is my current panel input:

I'm planning to hook up an electric Autometer quad gauge. Oil pressue, voltage, fuel and temprature. I got a oil pressure sending unit with the gauge. Here's a pic of the back of the gauge...


Second, I would like to do away with the headlight switch and go with simple toggle switches. I have a multimeter, would I check the connector for a constant voltage and then check which wire recieves power when I turn the switch on? The wires coming out of the plug are 2 orange, red, yellow and brown. Is it like a stereo where the yellow is constant and the red is power? I'd assume orange's would be power going to the parking/headlights and the brown would be ground?

I appologize for being so clueless. I also posted some similar questions in the s10 forum. Hopefullly there's no rules against that.