I noticed the same thing and started to go look for an adapter. Then, I said, I better check these fittings. Turns out, I had different fittings on the temperature probes for the
oil and water gauges, but that was OK because the fitting sizes in the manifold and
oil pan were different sizes as well and it worked out. You may be able to swap the sensor wires on the gauges if you have the same setup as mine. Just a thought.