I got together with my old engine builder some time ago and he mentioned the tendency of Chevy big blocks to have steam pockets in the cooling circuits around #7 and #8 cylinders. On many of his race engines (IMSA Corvettes, Air Race Airplane, and offshore engines) he plumbed relief lines from the back of the intake manifold forward to the thermostat housing. I've been contemplating running pressure relief valves (2 per motor) into high pressure hoses and dumping the steam overboard or may back into the thermostat housing. One "off the shelf" solution is the bronze water heater safety relief valves. I would like you to critique this concept. Thanks.