April 9, 2009
USAC Technical Bulletin
Junior Ford Focus intake restrictor plugs and intake tubes must be
installed in a manner that insures that all air entering into the engine
intake passes through the throat of the restrictor. When measured at the
narrowest point, the throat of the restrictor must not exceed .755
inches. The entry and exit taper dimensions, as measured with the
existing taper gauge, remain unchanged. Any attempt to allow air and/or
fuel to enter the intake through any other passage than the throat of
the restrictor will be considered an attempt to defeat the restrictor
and will result in disqualification or other penalties deemed
appropriate by USAC officials.