There are two main spots on an LS engine to mount an oil pressure sender. The first one is a port at the rear of the intake manifold, which is where the factory sender would mount, and the other is down near the oil filter. To mount your sender down by the oil filter you will either need an early piece like this one from a C5 Corvette, which is perfect for drilling and tapping. You could also use an aftermarket one like those sold by Turn Key Engine Supply. If you have the lower block-off plate, don't even bother trying to make it work, just find the right one. Auto Meter makes an adaptor for the oil port at the back of the intake manifold (PN 6541) so you can mount a gauge there.