Parts-Wise
replacement engine, crank case
90110753101
911(65-98) 911 turbo/GT3 (75-'11) 914-6 (70-76) Compression spring oil pressure relief valve
91110751200
911 (76-98) 911Turbo (76-2011) Oil pressure relief valve piston
93010753101
All 911 (78-98), 911Turbo/GT2 (01-12) Spring oil pressure relief valve, in right crankcase half