This head was milled which if ran with a stock head gasket would raise compression from 10:1 to 10.3:1 or run it with the included thicker Cometic head gasket for stock compression. Milling a cylinder head increases the engine's compression ratio by removing metal from the head's mating surface to make the combustion chambers smaller.
The head stud holes have been drilled for up to 12mm head studs. This head can be ran with 10mm, 11mm, or 12mm head studs.
CORE INFO: If you are sending in a core it must be in good condition with no machining, cracks, or damage. The core cylinder head must be received and inspected before this one will ship. Or select YES for the core and you will be refunded upon receiving a good core.
