GM introduced its High Energy Ignition (HEI) system during the 1974 model year and it soon became the standard on all GM cars and light-duty trucks. The HEI offered lowered cost and maintenance with dependability. The only drawback to GM’s HEI units was the spark advance curve was pretty much a one-size-fits-all proposition.

Not long after, a racer and hot rodder figured out a way to dial in an advance curve better than most others to get more out of a performance engine. Kelly Davis called this the Davis Unified Ignition and the technology has been handed down from Performance Distributor’s company’s founder.

Modern HEI Ignition Technology

Kelly’s son Steve runs the company now and is committed to keeping the company’s technology on the leading edge of the industry. For 2020, Performance Distributors has some new items that will excite the aftermarket automotive crowd.

“We are well known for the DUI (HEI) for Chevys, but we also have adapted its technology to Ford, Dodge, Toyota, and many other applications,” said Davis.

“At last year’s SEMA show we received several requests to see if we had a DUI Distributor for the 429 Caddy.  Although we already offered one for the 425-500 series, we did not for the 429.  After the show, we went to work and built a prototype, tested it, and now we DO have it available.”

Everything You Need

“This DUI has everything you need for the ignition in one simple unit. No external coils or spark boxes are needed. Just one 12-volt hot-wire hooked up to the DUI sends 50,000 volts of pure spark energy to the plugs for a cleaner, crisper, more powerful running engine,” Davis added.

Like the other DUI ignitions, the Caddy’s distributor relies mainly on a calibrated advance curve for its performance. A specially engineered weight and spring assembly are hand fitted and dialed-in using a Sun Distributor Machine for a precise timing curve.

“This provides instant throttle response and maximum power throughout the rpm range, without the chance for pre-detonation,” said Davis.

Davis also said their high voltage coil allows spark plug gaps to be opened up to a larger  0.055-inch gap. “The dwell in our Dyna-Module has been increased electronically to allow the coil to produce a longer duration spark.”

The combination of the larger plug gap and longer duration spark provides more complete combustion of the fuel mixture, which means more power and better economy.

For more information on the 429 Cadillac DUI Distributor, visit them online at performancedistributors.com.