-original 1/2 x 14 N.P.T.F.-, V8, Chevrolet 305 C.I., with factory gauges/Rally Gauges (correct resistance... see more-original 1/2 x 14 N.P.T.F.-, V8, Chevrolet 305 C.I., with factory gauges/Rally Gauges (correct resistance and connection, produces accurate gauge display)
-3/8-18 NPTF-, V8, Chevrolet small block, with factory gauges/Rally Gauges & aftermarket or 1981-up cylinder... see more-3/8-18 NPTF-, V8, Chevrolet small block, with factory gauges/Rally Gauges & aftermarket or 1981-up cylinder heads which have a smaller sending unit hole (correct resistance and connection, produces accurate gauge display)