Billet head kit for the 1991-1995 550SX aluminum reed cylinder engine. Domes are machined to a 76mm bore diameter with zero squish relief machined into the dome. Head design is all orings and does not use a head gasket. The head is designed to be installed with the water outlets on the intake side and has 3 water outlets available. Head kit includes domes, orings, and brass water fittings and plugs. This head uses the stock studs and nuts.
Compression readings are based on a stock cylinder taken at sea level.
This will NOT fit the 550 cast iron piston port cylinders.