Both end ports are machined with 8AN ORB (3/4-16 female) threads

Male Fitting Selection:a

8AN ORB Adapter Fittings can be found HERE

G02 X4 M40i

Cylinder Head O-Ringing Service, 6-Cylinder BMW Engines Series 1 Both end ports are machined5150 AutoSport Cylinder Head O Ring Installation Service for 6 Cylinder BMW Engines O ringing an engine cylinder head for high performance, high boost turbo applications provides several mechanical advantages. These advantages primarily focus on improving the engine's sealing capabilities and durability under extreme conditions. Price includes head resurfacing and wash. Key mechanical benefits of O ringing an engine cylinder head: 1. Superior Sealing: