Mopar distributors have some inherent design problems that although
are challenging can be overcome with the right equipment and knowledge.
problem is in the advance plate itself, if you disassemble the distributor
you'll see how it just sort of floats in a slot. As the vacuum advance unit moves the plate is doesn't stay
flat and true, it lifts up and down causing fluctuations in the timing
and an engine that just doesn't run consistent. Getting the correct initial
timing and limiting the total amount of Vac Timing helps to resolve this issue.
we like to use only mechanical advance (Stage 2) for performance applications
in cars that make less than 10" of manifold Vacuum at idle we can set the timing events by engine RPM and bring each event in
at a specific RPM for launch, shift points and reduce the chance of detonation
by limiting the total advance and at what RPM this occurs.
These numbers come
from about 40 years of tuning on dirt tracks, drag strips and muscle cars, these numbers are not
opinions they come
off a spread sheet that records the success's AND failures of all testing
done over the past 18 years and probably over 10,000 distributors including
1000's of Ford
position within the combustion chamber in an engine determines the total timing. For example in a Hemi engine
the plug is centered in the combustion chamber this characteristic gives the flame front a
shorter distance to travel and by allowing the flame front to travel 360* from ignition
point thereby achieving the maximum expansion point quicker. Timing
numbers in the 28-30* are correct for most hemi type engines. Looking at the
other common engines Mopar Wedge, Ford and GM if we study the position of the
spark plug or flame source and do the engineering calculations we'll come up
with ...Mopar 34* Ford 35* and Chevy 36*. These numbers will achieve
maximum expansion and pressure within the cylinder at our target of 13.4* ATDC
where optimum tork can be applied to the crank throw.
If your running 14:1, aluminum heads, C17 fuel or alcohol, dome pistons and
whizzing the thing to 8,000 RPM you may need more total advance, but again
these are all engineering formulas and calculations. Or you can do what
most guys do, start conservative and bump it up slowly until it slows down and
lock it. Just be sure that you A/F ratios are correct for each pass and
adjust the carb to the timing not timing to fuel curve.
The bottom line is, if we do our performance curve, phase and vac settings on your
distributor they perform flawlessly up to 8000 RPM and for $89.00
you won't find a cheaper or easier HP and drivability bolt-on anywhere.
Not to mention the ease of mind you'll have in knowing that there's no
detonation going on that you're not hearing over the roar of open headers,
loud street exhaust or your favorite Tex Ridder 8 track tape.
This is just a quick review of the information available
for your ignition system in our 47 page Tuning Guide available Via Email for
$10.00. Hard copies for $20.00 including mailing to the lower 48..
Click here to
learn more about our book.
We can curve your distributor or we have new distributors we can build to your
Mopar Performance Distributors
These distributors are not ready to run out of the box.
They have an extremely light set of springs that will bring your timing
in at about 1600 RPM and unless you have a 4000 stall convertor and 4.10
or better gear set in a 2600# car your timing is way to early and may cause
They are a pretty decent distributor and with the proper curve and phasing
they work well and can be used for most applications from an almost
stock to 11 second bracket car after they are set up properly.
All Distributors no matter who made them are Universal Fit,
meaning they fit nothing in the Universe. They are no different than a
set of Adjustable rocker arms, a carburetor or any other adjustable part, they
must be adjusted for the application.
You can not run a magnetic pick-up electronic distributor with a points style voltage
regulator, you must convert to either the new style electronic regulator
or use one of our Resto Voltage Regulators.
NOTE 2: Inductive ignition systems have a
max window of 7,000 RPM after that you should consider a CD type Ignition like
the Daytona-Sensors CD-1 or CD-Pro teamed up with a Hall Effects distributor
(Pertronix is our Preference) or a crank trigger system.
2 Pin/4 Pin Ballast Resistor
Unbolt the old ballast resister and install the new ballast
resistor in it�s place.
Note: The ballast resistors used from 1972 through 1979
had four terminals. The new performance resistor has only two terminals.
The two extra terminals fed the fifth pin used on the early ECU; and are
not required with the performance four pin ECU.
On the first connector of the new ballast resistor, plug
the terminal containing the 14-gauge brown wire onto one terminal of the
new ballast resistor. On the second connector, plug the terminal containing
the 16-gauge dark blue wire onto the other terminal of the new ballast
resistor. The unused terminal on each connector will be left empty. As
stated in step #5, they fed the fifth pin on the ECU and are not required
on the new four pin ECU.