For those that choose ease of maintenance along with performance gains, the single 44 HPMX is the set-up of choice. For all out performance, the way to go is the 44 HPMX. The 44 HPMX carbs in these kits have 30mm venturis and .55 accelerator pump jets installed. EMPI also has available a selection of jets if your application requires further dialing in. 44 HPMX Carbs have butterflies drilled for smooth idling. Complete kits feature Aluminum Center-Section Manifold, Aircraft Style Heim Joint Linkage, Chrome Air Cleaner with gauze element, gaskets and hardware. Complete with detailed illustrated instructions and attractive EMPI packaging. Fits Type 1 1600cc based upright engines.