apertures 26 are in the preferred embodiment formed in the front wall of the fuel injection conversion body 10 which defines the plenum 11 and may be partially defined by the front section of the lower housing 22 and partially by the front section of the upper housing 20 as seen in fig6 the primary axis x fig5 of the intake apertures 26 in this configuration is in the horizontal plane and is generally parallel to the engine crankshaft in a longitudinally mounted engine and consequently perpendicular to the crankshaft in a transversely mounted engine the intake apertures 26 are in the depicted embodiment defined within the upper and lower housings 20 22 the number size and shape of apertures 26 are selected to correspond to or cooperate with the number and shape of barrels or bores in the selected throttle body 100 the throttle body 100 may be attached by machine screws a gasket may be employed to seal the connection between the throttle body 100 and the fuel injection conversion body 10 to accommodate the engine bay characteristics of certain vehicle engine combinations the intake apertures 26 may be successfully positioned on the side wall of the plenum with only minimal if any decrease in.