It is called E.F.E. or early fuel evaporation. It does just what you said it does. Some systems used water, others used an electric grid under the carb, and others used exhaust gases (heat risers). Injected engines don't really need it, as it uses the valve for atomization and there is no fuel in the intake plenum.
One other note, on the early GM's that had the flat cam problems, it was caused by the heat riser. The vacuum switch in the t-stat housing that controlled the heat riser was out of calibration. It left the heat riser on all the time, and the block didn't expand as fast as the liters did. Too tight of a hole, flat cam!
One other note, on the early GM's that had the flat cam problems, it was caused by the heat riser. The vacuum switch in the t-stat housing that controlled the heat riser was out of calibration. It left the heat riser on all the time, and the block didn't expand as fast as the liters did. Too tight of a hole, flat cam!
