Here's how the factory did it...
The factory offered a banjo bolt and fitting that screwed into the same threads where the low oil pressure warning light is. The low oil pressure warning light then screws into the banjo bolt, and the banjo fitting has the oil pressure gauge fitting.
Uncle "Richard" Douglas has a Land Rover with big wheels that never gets stuck... until he breaks something so it won't go. Uncle Douglas always breaks something. - Anna Crowther at the Conclave 2012 (AKA Carburetor Neck)