The oiling system on the small-block V8 engines now requires the use of a unique oil filter, and the oil pressure sending unit is not readily accessible. GM-47971 is installed in place of the spin-on oil filter and allows the existing oil pressure gauge GM-21867 or GM-21867-A to be attached for engine oil system diagnosis. GM-45299 Engine Pre-Luber can also be attached to pre-lubricate the engine before starting a replacement engine.
Requires a 1/8 " NPT thread adapter if using an aftermarket oil pressure gauge.