At the heart of all Roger Clark Motorsport engineÕs is the now world renowned RCMS Modified oil pump. This clever, effective modification has been designed to assist the Impreza with itÕs oil supply and is now regarded as a must have modification with any Impreza engine build. Each pump is carefully checked, given a serial number and then modified to incorporate a different pressure relief valve ensuring greater reliability and peace of mind to your Impreza engine. Please note that flow rate remains unchanged. Our oil pumps are supplied with a replacement front crank oil seal and oil gallery, black sealing o-ring. It is also recommended that you use 3 bond sealer (SGA35) to seal the oil pump to the block assembly.