Properly firing your engine's ignition is a necessity for good combustion-thus power. There are many aftermarket ignition choices for the RB Wedge and Hemi that offer added voltage to the spark plugs. Some long-time readers may recall we tested Performance Distributors (PD) 440 D.U.I. (Davis Unified Ignition) ignition back in our March '04 issue (Fire That Big Block). Nevertheless, that D.U.I. distributor is still under the hood of our 67 R/T test mule. Just a reminder, the 440 D.U.I. distributor only fits under the hood of non- Shaker, Air Grabber and Ram Charger equipped Mopars with stock type valve covers.

We were jolted to hear Performance Distributors has developed a Hemi D.U.I. distributor that clears the fat Hemi valve covers. One drawback-limited applications due to hood clearance. For Performance Distributors to offer a Hemi D.U.I. they needed to lengthen it 11/2-inches more than the 440 D.U.I. causing hood clearance issues. The benefits of the fatter/wider distributor are reduced spark scatter between the terminals, which leads to a smoother running engine. Inside the distributor is the Dyna-Module that adds dwell time for longer spark duration to ignite the combustion more completely. The coil, also inside the distributor cap, is a high voltage (50,000 volts) unit. All it takes is one 12-volt wire to power the D.U.I. ignition.

For a trial fit of the Hemi D.U.I., we used our '67 Coronet R/T. The tall distributor managed to fit under the hood when we used a stock type coil/cap cover (see captions 4, 5, and 6). It's most likely the Hemi D.U.I. won't fit under the hood of a Hemi A-Body unless the motor was in a lower than stock location.

Fortunately, we were able to test the new Hemi D.U.I. using a brand-new Mopar Performance 528 Hemi crate engine at Ray Barton Racing Engines (all MP 528 Hemis are now built at Ray Barton Racing Engines). Before any MP Hemis are crated and shipped, they're dyno tested on Barton's DTS engine dyno for quality control. The 528 Hemi used for our ignition test was only the 17th Hemi crate engine that Barton's had built at that point. By the time you read this, RBRE will have built, dyno-tested, and shipped over a hundred MP 528 Hemis. Call any MP dealer to order your Hemi, not RBRE. Questions can be directed to the MP tech line: 888-528-HEMI.

The brand new 528 was run at 1,800 to 2,200 rpm for 25 minutes to properly break-in the flat tappet hydraulic cam and lifters. During that time, they monitor the oil pressure, water/oil temp, and check for any possible leaks. Afterwards, the valve settings are rechecked before any dyno pulls (usually three before crating) are made. Barton's dyno distributor is an MSD Pro Billet piece, using Moroso Blue Max ignition wires and an MSD 7AL ignition box. On its first pull the 528 made 642 hp at 6,200 rpm. By its fourth pull, power was up to 647 hp. We pulled out the MSD distributor, dropped in the D.U.I. and set the timing at the same 30 degrees full advance. The D.U.I. worked alone without the help of the big 7AL and MSD Pro Tower coil, using only one 16-volt wire to run. On its first pull the D.U.I. tied the MSD in power production and the Hemi marched on making more power as it continued breaking in. After three more pulls the 610 hp (rated) Hemi was putting out 650 hp at 6,200 rpm! The Barton's (Ray and son Dave) commented that these new Hemis need over 20 pulls before power stops climbing. Dave reinstalled the MSD ignition to demonstrate, and the Hemi backed-up the 650 hp. This only verified the MSD Pro Billet/7AL vs. the D.U.I. was a dead-heat ignition duel. It was senseless for us to make any more pulls (these crate Hemis usually get 3-4 pulls); we'll let the lucky new Hemi-owner enjoy breaking it in.