The 40 IDF is truly the mileage champ. 40 IDF carburetors are factory equipped with 28mm venturis that help provide a terrific combination of fuel economy and performance. The Weber IDF series will fit comfortably under the engine deck lid of VW bugs, buses, and square backs. Smaller 1600cc and 1776cc engines will benefit from the increased port velocity and enhanced engine torque produced by Weber 40 IDF carburetors. Our top quality 356 aluminum alloy manifolds, air filter hardware and Cross Bar Linkage provide exact throttle control and maintain adjustments between service points. Complete kits are available to fit most Dual Port VW and Porsche applications. (Velocity Stacks are not included in 40 IDF Kits)