Im looking into getting a 3 gauge pillar and I got 2 gauges I want but cant think of the third besides the engine oil temp but I was wondering if there was a plug or something on the pan to put the 1/8 npt plug for the sensor.

 

Not sure on the LS1 but look around where the oil filter goes on, on the LT1, there is a plug just above the oil filter that can be removed to install a mechanical gauge.