The FR range of bolt on air horns are designed to fit both side and vertical draught Weber and Dellorto carburettors as well as throttle body equivalent set ups with 65mm bolt centres. The full radius design accelerates the air into the inlet to improve air flow. The FR48/SP is for Weber 48 DCO'SP carburettors only
Whenever an ITG filter replaces an original equipment inlet system, the fuel metering systems on an engine may need adjustment to compensate for the change in air flow capacity. (The full engine range should be checked on a rolling road).