The oil pressure sending unit is located next to, and a bit higher than, the oil filter on the back side of the oil filter adapter. It's easy to get to with the right front jacked up and the wheels turned to the left, or with the passenger front off. Most likely, you will have to use an adapter because our sending unit uses a different size/pitch hole than most gauges. There should be a small assortment of adapters that come with the gauge, however.

EDIT: It took me 4 minutes to write this??? Dang, Chris, you beat me to it... lol