These CNC-ported big-block heads are available with and without valves. In this case, the heads shown do not include valves, however, the heads are sized for 2.25-inch intake and 1.88-inch exhausts. Intake valves with a 0.250-inch longer stem length and stock stem length exhausts are recommended. Note the bronze guides. The heads are engineered to accept 11/32-inch stem diameter valves.