We decided it was time to replace our Mallory Breakerless Ignition and Mallory high performance coil after being plagued by hesitation, slugishness, hard starts, dieseling and an overall desire for better gas mileage.

Overtime we had replaced most if not all of the ignition system on our 78 J20 including plugs, wires, ballast resistor, new Mallory coil and the guts of our Mallory Breakerless ignition in order to fix these problems which persisted.
We had heard good things from fellow jeepers about the D.U.I. Performance Distributor and the performance gains and results they acheived so we thought we would give it a try.

The J20 just didn't have the power it used to have hauling our 78 Mapleleaf camper up hills, around to shows and camping. Not to mention performance on the street was less then desirable as well.

Steve Davis of Performance Distributors and his team set us up with the AMC D.U.I. Distributor for street and strip part no. 40820. While we were at it we also got a set of high performance Live Wires and wire looms from Performance Distributors to compliment the install.

Steve's Dad Kelly Davis actually designed the industries first H.E.I. Performance Distributor based on his background of drag racing and hot rodding. Performance Distributors is now the most respected in the world for their advance curve technology distributors.

Each D.U.I. Performance Distributor is a one piece ignition system for AMC's. It includes an internal coil producing a whopping 50,000 volts of power and a Dyna module.

This design and it's simple one wire hookup enabled us to throw out the pesky ballast resistor and coil taking up space in the engine compartment, talk about cleaner looking.

Since the D.U.I. Distributor is somewhat larger then the Mallory Breakerless distributor we had to move our stock fuel line over a bit. While we were at it we also replaced the fuel hose to the carb as well.

removing existing ballast resistor
Existing coil and wires before D.U.I. Performance Distributor install
All the parts we removed that were no longer needed.

Cleaning up the engine compartment.
finding TDC
Steve recommended using a set of Autolite Platinum spark plugs and a running gap of .055" instead of .035" which we were running with the Mallory ignition setup.

The increased voltage and wider plug gap creates a more powerful explosion of the fuel mixture which increases horsepower, performance and fuel savings more on that later.

Overall the installation was pretty straight forward and the directions provided with the 40820 Performance Distributor were very easy to understand.

After removing the ballast resistor and coil the one wire hookup was a snap. The ballast resistor which actually reduces voltage had been a problem for us in the past and we were glad to see it and the coil go.

Mark the Shark installing our new D.U.I. Performance Distributor
and new "Live Wires" sparkplug wires from Performance Distributors
Unlike our Mallory Breakerless ignition the D.U.I. Performance Distributor came with a new distributor gear which means we didn't have to hunt one down like the last time we installed a new distributor.

Once the distributor was in we took advantage of the built in tach terminal on our new D.U.I. Distributor and installed a tachometer to assist with tuning.

After the install we fired up the 401 for the first time then we adjusted the timing per the instructions provided and then adjusted the carb.

One of the first things we noticed was the engine now fires right up with one turn of the key. We were also able to achieve a nice smooth idle at 500 rpm's which we were not able to do in the past.

Road testing was a thrill, right away we noticed an increase in horsepower out on the highway. Back in the driveway when we shutoff the engine, no dieseling "another bonus".

We wanted to see if there would be any savings at the gas pump with our new D.U.I. Distributor so before beginning this project we calculated our gas mileage to be 12 mpg. Once the install was complete we recalculated our gas mileage again and we are happy to report we are now getting 14 mpg. That means more money in the wallet for other jeep projects that's a plus.

Since the install we have been very happy with the overall results. We have hauled our truck camper to several shows and the street performance has been incredible. Climbing hills is no longer a problem even hauling all that weight and throttle response is a thrill.

As you can see from the pictures the D.U.I. Distributor really cleaned up the engine compartment and makes a great presentation at shows. The set of Live Wires and Billet Aluminum wire looms from Performance Distributors really topped off the install to. The Live Wires have a heat resistant sleeving so you don't have to be concerned about your headers cooking your wires. They also come with a durable long lasting high temp silicone jacket insulation and are spiral wound so they will not interfere with your radio or computer. In addition the heat shrink between the boot and sleeving keeps the dirt and moisture away.

The best part is the Live Wires offer an extremely low Ohms per foot for optimum spark. Not only do the Live Wires look great they are also easy to install and no assembly is required as each wire is numbered on each end for the correct cylinder.

Overall we are very pleased with our new D.U.I. Performance Distributor, it is one of the best performance upgrades we have done. Best of all it put all of our ignition problems behind us so we could get back to having fun with our Jeep truck once again.
Hitting the open road with our 78 Jeep J20 with camper
Performance Distributors has a whole line of D.U.I. Distributors for Jeeps which even includes the Tornado engine. See the list below for even more jeep engines. Then visit their website at PerformanceDistributors.com to find a D.U.I. Performance Distributor for your jeep.

52720 AMC 4 Cylinder DUI (Street/Strip Version) 2.5 Liter, 1980-1981
40420 AMC 4 Cylinder DUI (Street/Strip Version) 2.5 Liter, 1983-Up
40620 AMC Inline 6 DUI (Street/Strip Version) 232-258 cid
40820 AMC V8 DUI (Street/Strip Version) 290-304-360-390-401 cid
40920 AMC Tornado 6 Cylinder DUI (Street/Strip Version) 230 cid
408211 AMC V8 DUI (Racing Version) 290-304-360-390-401 cid (w/ Vacuum Advance)
408212 AMC V8 DUI (Racing Version) 290-304-360-390-401 cid (w/o Vacuum Advance)

We would like to Thank Steve Davis and his Team at Performance Distributors for helping us pick out the right Distributor and accessories for our application and assisting us with any questions that we had. They were both knowledgeable and helpful.

Thanks also goes out to Mark the Shark at Rad Customs in Morrisville, PA for installing our DUI Performance Distributor and Kevin Kieffer for fine tuning our J20. Also a big Thanks goes out to Tom Smith at Direct-A-Friend Pictures for providing the photography for this article.