FYI Sears has a gun that develops just over 600 ftlb.
My Corvair had a heating problem, in about 2 blocks the water temp was pegged. Inspection showed no bubbles in the radiator. I had to get a kit to test for exhaust gasses in radiator, it is a realy good idea if this used to lower the water level a bit. The fluid finally turned yellow the second time around. There was an almost imperceptible track between two cyls. New gaskets and a BIG radiator and it was my dd for 2 years with no further problems.