-3/8-18 NPTF-, all V8, Chevrolet small block, with factory gauges & aftermarket or 1981-up cylinder... see more-3/8-18 NPTF-, all V8, Chevrolet small block, with factory gauges & aftermarket or 1981-up cylinder heads which have a smaller sending unit hole (correct resistance and connection, produces accurate gauge display)
all 1st design: 3 wires connect to each door ajar switch, each switch has 3... see moreall 1st design: 3 wires connect to each door ajar switch, each switch has 3 holes in a plastic insulator to accept pin type terminals on wires from harness