is there an oil galley plug that can be removed in order to install the compression fitting for a oil psi gauge or do i have to tee into the oil light sender location below the filter?

If you want the light an the gauge and don't want to drill anything a pipe-T is needed. The hole in the pump body is 3/8" NPT so a reducer bushing will likely be needed for the mechanical gauge connection.

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Joshua

late 70s and 80s era v-8s and slants often came with a factory pipe-t screwed into the oil pump (slants) or the top rear of the block near the distributor (v-8s). These typically are tapped for the right size fittings to run both a gauge and a light.