I just picked up a Gauge and taco plate with sender. Both are OEM Porsche 914.
Question is since my car did not have the temp Gauge (Parking brake flasher instead) is the wiring in the car from the factory to hook up the oil temp Gauge as it was an option?

I do not have the optional center console with the aux gages either, but I did see some extra wires in the tunnel with connectors not hooked up to anything. Also is there a wire for the sender in the engine compartment already there?

Should be pretty easy to do just one wire.

I think you will be able to use the console wiring that should be present in a '74. You need +12V power to the gauge, ground to the gauge and signal to the gauge from the taco. In the wiring to the console harness, there is your +12V. A home-made wire, with appropriate spade terminals, would allow power to the gauge to where ever you decide to mount the gauge. A homemade wire for ground similarily. Once you install the taco sender, you will make a homemade wire from the taco sender, across the engine mount bar to the connector in the wiring harness that is just under the battery tray. The wire in the harness enters the interior and terminates in the vicinity of the shifter for connection to the console harness. You should check the wiring diagrams on pelican to identify the color code of the wires you are looking for. Piece 'o cake

There should be a wire for the temp sender in the engine compartment with the fuel pump wires. And I bet the spare wires in the tunnel are for the center console. Check the wiring diagrams for the color of the wires.