Chev 350 5.7 Vortec Water Neck Riser GM 604 Engine Circle Track Sprint CII-50001Chev 350 5. 7 Vortec Water Neck Riser GM 604 Engine Circle Track Sprint CII 50001 The CII 50000 Crate Engine Water Neck Riser has two 3 8 NPT ports raised above the centerline of the block. These ports are raised so the bypass lines running to the rear of the intake manifold on a GM 604 engine will not lay on the manifold. It also has a 1 8 NPT port in the center of the block for utilizing a water pressure switch and a 1 4 X 20 tapped hole for a