Proflow Water Neck, Thermostat Housing, Spacer, Suit SB & BB Chevrolet, 2x 3/8'' NPT Ports, Billet, Black - PFETH-CSPPart Number: PFETH CSP Our water neck spacer for the SB & BB Chev engine adds 2x 3 8" NPT auxillary ports which can be used to add coolant lines or sensors, including a water feed for your turbocahrger or supplying extra coolant to the rear of the cylinder heads. Includes high temp Viton o ring Height = 27mm