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
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
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
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
All the parts we removed that
were no longer needed.
Cleaning up the engine
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
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
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
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.