“Lightin’ ’em up” can mean a whole lot more than just hazing a pair of tires. All of those who have assembled their own muscle car’s engine know how imperative the combustion part of “internal combustion engine” is, and getting that right boils down to one singular point – ignition. Getting that pulse to the spark plug at the right time of the reciprocating assembly’s revolution is the difference between getting all the cylinders to fire in the correct sequence or a dead start.

In a world of late-model conversions, fuel-injection kits, and electronic engine management systems, us old school loyalists might feel a little endangered. Every which way we turn, we’re barraged with “Ditch that points distributor!” and “You’re still running a carburetor?” Listen, there’s no shame in “keeping it real,” but that doesn’t mean that you have to live in the stone age, especially when it comes to spark management. For those Bow Tie enthusiasts still employing the tried-and-true H.E.I., the folks at Performance Distributors, makers of the GM Street/Strip D.U.I. Distributor have some good news.

We got our hands on a pretty-decent running ’72 Chevrolet Nova that’s been put through the paces a couple times and makes some pretty good power to the floor. The problem is that this stout little A-Body is still running an H.E.I. distributor. Borrowing Jon Rasmussen’s Nova for the day, we sought out to compare how this stroked 388 small block would run with a new D.U.I. S/S distributor versus the factory ignitor in a face-to-face shootout. What we found was pretty impressive.

First, The DUI Difference

The Street/Strip (or “S/S”) D.U.I. employs all the benefits of the General Motor’s High Energy Ignition or “H.E.I.,” namely the incorporation of the ignition coil into the distributor by mounting the coil to the top of the cap. Yet, unlike the stock unit, the D.U.I.’s high output spark comes from the company’s 50,000-volt coil and unique Dyna-Module. The dwell in the Dyna-Module has been electronically-increased to allow the coil to produce a longer spark. And, the longer (and fatter) the spark, the better the ignition.

The Davis Unified Ignition (D.U.I.) is the ideal next step for those currently running a factory-style GM H.E.I. ignition. With no external coils or spark boxes, the D.U.I. requires a single 12-volt “hot wire,” and is designed as a direct replacement for your old four-pin ignition.

Of course, Performance Distributors’ D.U.I. ignition systems aren’t just for GM vehicles (Cadillac, Pontiac, Oldsmobile and Buick), but also feature applications for Ford and Chrysler, which previously, were hindered by fitment problems (primarily low hood, ram air base, cylinder head-clearance issues). Now, the D.U.I. is available for a wide array of vehicles including supercharged applications for the V6 Ford, turbo Buick V6’s, 4-cylinder Hondas, Toyotas, PT Cruisers and Neons, as well as a variety of cap colors including blacks, blue, red, yellow or even clear!

For those Ford and Dodge enthusiasts who would rather run a non-H.E.I.-style distributor, Performance Distributors does have ignition systems for you, too. Removing their 50,000-volt coil from the cap back to a standard-style coil, buyers can use a separate “Dyna Mod” module for their Ford “4-bangers.”

Performance Distributor’s Dyna-Module increases the dwell. That, with the high voltage coil (which allows spark plug gaps to be opened up to a massive .055-inches), produces an ideal combination of a larger gap and longer duration spark.

We were drawn to the Performance Distributor’s D.U.I. S/S ignition for a couple reasons, one being the complete comprehensiveness of preparation that goes into the D.U.I. ignition. Each of these distributors are tailored to your particular vehicle. Using special weight- and spring-assemblies, each distributor is hand-built and dialed in using a distributor machine to calibrate the right timing curve to match the specifications of your specific engine.

Performance Distributors modifies and “dials-in” each D.U.I. distributor to match the perimeters of each customer’s engine set up. Before Performance Distributors could build us a distributor, we needed to supply them with plenty of information, including compression, carburetion, cam grind and anything else we could dig up.

“Whether your engine is bone stock, mildly modified or heavily modified, we can tune a DUI for you,’ Performance Distributor’s Steve Davis stated. “Each Performance Distributor is custom-tuned on a distributor machine with a super smooth advance curve. A custom advance curve insures maximum performance and mileage. Buying an ‘uncurved’ distributor would be like buying an unground camshaft! No compromise curves…no guesswork for you. Just pure power from the world’s leader in high performance advance curves.”

Putting It To The Test

We don’t care what year, make or model, semi-gloss black just speaks “hot rod” to us. We’ve even wondered what our daily driver would look like “ratted out.” Jon Rasmussen’s ’72 Nova was a perfect Guinea pig for our D.U.I. install.

To put Performance Distributor’s claims to the test, we grabbed So Cal native, Jon Rasmussen’s rat-rodded ’72 Nova. Don’t judge this Chevrolet by its cover, either. Jon took this once blue grocery getter to the recent “Run to the Coast” autocross event earlier this year and put his Nova through the paces. Outfitted with a 388 cubic-inch small block spinning a Comp Cams bump stick with 224/230 duration, pair of Dart Iron Eagle 210cc heads sit a top the stroked block while aftermarket slugs squeeze the chambers 10.25:1 compression, still very much 91 octane-friendly. Topped with a RPM Airgap intake and a 750cfm Holley mechanical double-pumper, the little “mouse” motor sure has plenty of bite.

Before we could do anything, we needed to make sure Jon’s Nova was running right. With the H.E.I., Jon’s Nova ran at 16-degrees of base timing and 36-degrees of top timing. Performance Distributors insists that their D.U.I. distributor is a “drop-in replacement” for the H.E.I.

Knowing what we were working with, Performance Distributors provided us with their top-of-the-line “LiveWires” plug wires. Wrapped in “space age” heat-treated, inflammable, and non-corosive glass braid resistant sleeving, each set of Livewires – much like your D.U.I. distributor – is custom fit for your application, meaning no cutting necessary. Protected from -76 to over 1400-degrees, these plug wires are available either over-the-valve cover or under-the-header applications. More importantly, these wires feature a spiral wound core that prevents electric interference. Capped at both ends with durable silicone jackets and insulation that are individually-numbered.

Performance Distributors’ LiveWires feature heat-resistant sleeving that protects the plug wires from under-hood temperatures and are inflammable, resistant to moisture and chemicals, and are custom fit, so no assembly is required. And for those who regularly forget your firing order, each wire is numbered on both ends.

Equipped with everything we’d need to make the swap, we got to work pulling our Nova’s old and worn H.E.I. and rubberized plug wires. First, as always with anything electrical, we disconnected the battery, unplugged the vacuum line running to the vacuum advance, and uncorked the boots from the spark plugs, careful not yank out our wire terminals. Next, we removed the H.E.I. cap, and unscrewed the bolt for our distributor hold-down clamp. With that, we marked our rotor position, and our H.E.I. came right out. (Editor’s Note: Make sure to pull the distributor shaft out vertically. Pulling at an angle might catch the distributor gear with the camshaft.)

Lining up our original H.E.I. to our new D.U.I., we measured just to be sure that the new distributor was identical in length and diameter. While this was an unnecessary step, Performance Distributors guarantees complete product superiority and customer satisfaction, so even if there might be a mishap, Performance Distributors will make sure you have the right parts. With everything lining up perfectly, we were ready to drop our new D.U.I. into place.

The choice to go with a D.U.I. was a no-brainer. While a well-tuned H.E.I. can produce up to 40,000 volts (compared to 18,000 volts typically produced by a points system), Performance Distributor’s D.U.I. cranks out 50,000-volts, which provides a superior spark and ignition, quicker starts, smoother idle and (believe it or not) better fuel economy.

Next, we removed the D.U.I. cap, careful to position the rotor to the same position as the H.E.I.’s rotor. Lowering the shaft into the engine, we were mindful to engage the oil pump without “bottoming out” our gear. This can cause unnecessary – and if gone unchecked, detrimental – wear and tear. With our distributor in (with the included new gasket), we hand-tightened our hold-down clamp, reattached our D.U.I. cap, and attached the vacuum line and our new “Livewires” plug wires. Sure enough, our Performance Distributor D.U.I. was a drop-in replacement. Now, let’s see how it ran.

With our D.U.I. installed properly, we hand-tightened the hold-down clamp and plugged in our new “LiveWires” plug wires. Performance Distributors threw in a set of these billet wire loom. Using the supplied battery and tachometer connectors, we also recapped the live wire to the battery and wire to the tachometer.

Using our trusty timing gun, we tried to run the idle-happy 388 small block at the recommended 12-degrees (around 600 rpm), but found that this Nova preferred a little more oomph in the way of base timing. We landed at an increased 18-degrees of base timing over the previous 16-degrees. But, at throttle, we registered the same 36-degrees, loosing 2-degrees of vacuum advance. While this might alarm a few of you, we found that the proof of the D.U.I.’s superiority was in the pudding.

powerTV shop tech, Sean Goude, earned his money wrenching on Jon Rasmussen’s small block ’72 Nova. While we suffered a couple hiccups getting the timing right, the end result was a great-running, street friendly, asphalt-pounding power delivery and torque curve. We were all smiles when this little mouse motor pulled an impressive 299 rear wheel horsepower and 343 foot lbs. or torque.

Finding our 388’s “sweet spot,” we sought out to make a good, solid dyno pull to see how our new D.U.I. S/S Distributor fared versus the original factory H.E.i. ignitor. Pulling the Nova all the way up to 5,000 rpm, we watched our dyno’s computer read an impressive 299 horsepower while the small block’s torque output peaked at 343 ft. lbs. around 4,200 rpm. While those numbers are what we expected for the mouse motor, what wowed us was how significantly smooth our graph was.

Even with the “smoothing option” turned off, our Nova’s dyno pull was exceptionally smooth; a testimony to the improved ignition advance curve provided by a custom-tuned D.U.I. distributor with a vacuum advance withing with a coordinated mechanical advance.

With our timing set and our engine idling comfortably, we fastened down the hold-down clamp (careful not to nudge our DUI distributor for fear of altering our setting), double-checked our LiveWires’ connection to the plugs and cap terminals, and arranged our wires using the billet looms included with our package. Arranging plug wires isn’t just for aesthetics, either. Depending on your exhaust system, whether you use factory manifolds or headers, you’re going to need to be mindful of how your wires reach the plugs. Too close to the header tubes and you might find yourself unnecessarily burning through sets of wires (although, the LiveWires are exceptionally heat and fire resistant). Using the smaller looms first, we paired the plug wires up towards the cap, not the other way around.

Without a doubt, we were all witness to the D.U.I. Street/Strip Distributor’s advantage over the factory H.E.I.. While the Performance Distributor unit wasn’t a “magic bullet” that unlocked all sorts of hidden horsepower, what the distributor swap provided us was a smooth, reliable timing advance curve without hiccup, pause or backfire. We were unanimously impressed with the D.U.I.’s ease of installation, direct replacement quality and top quality fit-and-finish. If you’re looking to maximize the drivability of your muscle car, hot rod or ride, the D.U.I. Street/Strip H.E.I. distributor replacement is the way to go.

Your Distributor, Made To Order

So, we’ve seen this difference the D.U.I. Street/Strip distributor makes on this small block Nova, but what about your car? The greatest thing about Performance Distributor’s D.U.I. program is that it’s completely tuned to yourcar. We talked to Performance Distributor’s Steve Davis and he showed some light on how unique each one of their D.U.I. ignitors are.

Each DUI distributor housing is “turned down” on a lathe by hand. Cleaning up the stock cast housing, by turning it on a lathe and then polishing it, gives the D.U.I. a sharp, clean look.

Before the Dyna-Module installed, dielectric grease is applied to the bottom of the module. The grease transfers the heat from the module to the distributor housing, which in effect, becomes a heat sinc. The dielectric grease can mean the difference in lasting five years versus five minutes. Performance Distributor’s Dyna-Mod is designed with more electronic dwell time than a stock H.E.I. module. The additional dwell time of 2-to-3 degrees throughout the rpm range allows the ignition coil to saturate longer and produce a more intense spark at the plugs. This concept is analogous to older distributors switching from single to dual points to achieve improved performance.

Note that Performance Distributors uses nylon rotor hold-down screws because, as owner Steve Davis states, “Sometimes metal screws will act as a ground, which voltage will try to jump to. Using these eliminates that possibilty.” The cap, which contains the D.U.I. coil, is patterned after the factory GM H.E.I. in design.

The final step before shipping is to test fire each D.U.I. distributor for spark. Davis continued, “They are not randomly tested, EVERY one is test fired.”

So there it is! While you might be thinking that such subtle differences might not make a whole lot of difference, the facts show that a longer, hotter spark provides your muscle car with more complete fuel combustion, providing your ride better fuel consumption, economy and ultimately horsepower, because that’s the final goal after all, right?