Oil sending unit/switch

All electric oil gauge senders that I'm aware of are "big." If it won't fit the stock location on your engine, find out if there is an alternate sender tap, or if not, you'll have to space it away from the engine with pipe fittings. Many guys like to use a tee so that they can retain the original oil warning lamp along with the gauge.

All these senders use U.S. pipe thread.

1/8 pipe thread is approx. 3/8" outside diameter

1/4 pipe thread is approx 9/16" outside diameter

3/8 pipe thread is approx 5/8" outside diameter

These are approximate, but with pipe thread, there is nothing in between. If you buy fittings be careful not to mix in other fitting types such as flare