PLEASE HELP...Heater Problem

From : barbara

Q: the purpose of a throttle body spacer is to move the carburator fuel feed points out of reversion turbulence. a carburator is ignorant and it depends on a vacuum signal generated by the venturi effect of ingested air passing across a venturi to draw fuel from the bowl through the main jet. anything that disturbs a laminar airflow inhibits correct fuel mixing. when a high performance cam is used the valves are opened earlier and closed later than the factory cam which generates more airflow and hence more engine power but only when the air volume is large enough and the inertia of the air column is great enough. however at lower engine speeds the air in the inlet manifold and the exhaust pipes actually move both in and out. this reversing of airflow creates soot on the carburator from exhaust gasses as well as disturb smooth engine performance at low speeds. since fuel injection systems do not depend on this vacuum signal for fuel delivery a spacer does nothing. steve does a throttle body spacer really give you up to 20hp gain and 4mpg gain or is it just a wast of money ive herd both postive and negative about them. thanks .