Spark plug Bosch W8DC for 518 from 07/1975 up (518 LHD 4625659 / 518 RHD 3820624) and for 518i+520/4+520i all years of manufacturing only for country version AUS, S, you need 4
1 BOSCH W8DC spark plug for Porsche 928 from 1978 to 1982 99917017090 - RS32155 - Mecatechnic.com