Performance Air Filters for Weber Carburetted Jaguars. Horsepower is primary in importance on the competition engine, but so is clean air. Filtering out even the finest dirt particles can extend the life of any piston engine. This set-up is specifically for 45 or 48 DCOE Weber carbs on XK engines with enough stand-off (3) for long airhorns. Advisable for racing or hi-performance applications only.