Davis Unified Ignition (D.U.I.) HEMI Distributors are a high performance, one piece ignition system capable of pumping out 50,000 volts of pure spark energy. Since the efficient design of the hemispherical combustion chambers require less total timing than other engines, the HEMI D.U.I. distributor is calibrated on a Sun distributor machine with a precise timing curve for optimum performance. No external coils or spark boxes are needed, just one 12 volt hot wire hook up for a cleaner, crisper, more powerful running engine. These distributors provide instant throttle response and maximum power throughout the rpm range with no pre-detonation. Whether your engine is bone stock to highly modified, D.U.I.'s HEMI distributors deliver quality, reliability and performance that is unmatched. Perfect for both crate engines or early production HEMI's. Due to space limitations, these distributors are built without a vacuum advance.