This new 15 degree aluminum cylinder head is designed for small displacement racing engines that run competition eliminator. This head is identical to the 18 degree head except the head is rolled by machining the deck surface at a 2 degree angle and thereby removing more material from the exhaust side of the head than the intake side. The valve guide holes are also tipped 1 degree in the casting to produce a total 3 degree in valve angle. Smaller combustion chambers are the main advantage. The head does not have valve seats or valve guides and has 35 to 37cc chambers instead of 42 to 44cc in the 18 degree head. P/N is made from the same casting as the 10134364. This is not a CNC ported cylinder head.