Description Reviews MINI Cooper S thicker head gasket is in stock and ready to ship! This is a MINI OEM thicker head gasket and the only gasket we use on all of our engine builds. Stock is .90 mm (.035 inch) thick, this gasket is 1.20mm (.047 inches) thick. This is a 5 layer gasket to be able to take all the boost and heat of a built engine. We have used this gasket to over 500 HP and up to 28 lbs. of boost in testing. A new gasket is required anytime you modify or replace the head on your MINI. This head gasket is specially designed for engines with an aluminum head. Will fit and work on all Gen 2 MINI Cooper S's with N14 or N18 engine (R55, R56, R57, R58, R59, R60, R61).