For the racer that is running a cooling system on their hot rod these ported billet alum. water blocks make plumbing a cooling system as simple as it gets. The water blocks are machined from billet alum., O-ringed on the backside and use a -12 ORB fitting provision to give the racer plenty of water flow. Mounts using 3/8" bolts on .250" thick mounting surface and blocks are .700" thick overall. Water blocks are sold each and racer can choose from alum. machine finish or black anodized from drop down menu.