Porsche Hastech Engineering Porsche 911 Crankcase Ventilation Oil Blow by Separator H911 106 KIT SMC 16 172 18x10 Measures 5mm x 130mm SMC000805 Natural #21 Lrg Measures 5mm x 130mm ARP Head Studs or equivalent head studs recommended Features and Benefits:Reduces the oil blow by from the crank ventilationKeeps the oil in the engine while still allowing good crank ventilationVery simple mounting sandwiches between the crankcase and ventilation the lid breather coverUsed on all Hastech race & street enginesRecommended for all aircooled Porsche 911 engines to help reduce oil consumption caused by ingestion of oil laden air into the intake caused by excess crankcase windage and blow by Fits all aircooled Porsche 911 models from 1965 through 1998