My girlfriend Kate insisted I add this picture. It's nothing to do with distributors, but she took it after my epic battle with fitting a lightweight starter motor. Chris Miller had already fitted what should have been the identical model to his car with no problems, but the one I was fitting had an additional casting lug, which prevented getting a socket on the bottom fixing stud.

I considered pouring petrol over the car and claiming the insurance at one stage, but this is a picture of me, Boo, and the dead 33 year old starter. Kate took this because I was in Black Country terms "reesty" (unspeakably dirty). There are also a couple of pictures of the lug on the motor causing the problem.

 

After experimentation with the standard distributor, it was apparent that increasing the ignition advance can give great benefits to not only engine performance, but to fuel economy, with 136-8779 returning 16mpg on a Monday Club trip to Scotland cruising at 80-85mph.

The problem was limiting the amount of total advance the distributor gave to prevent "pinking". To read up on ignition advance, and modifying a standard distributor, read the original article.

A conversation with Jensen Guru Dave Barnett revealed that Mopar make a distributor that is adjustable for the rate of ignition advance AND the amount of total advance, which is just what I was looking for.

https://www.campbellenterprises.com/mopar-performance-ignition-electrical-parts.htm quick part number search P3690432 found the distributor required (see picture below).

 

It undersells itself on most parts sites being simply described as a "performance advance curve" distributor, rather than as an adjustable one.

There is a version of this distributor for the 383 engine, but it is a different part number due to the 383 dizzy having a shorter drive shaft. Unfortunately, Scoggins Dickey do not have a great parts listing, so an e-mail will be required to get the 383 part number.

You will also need MAL29014, which is the Mallory ignition adjustment kit. This had the adjustment keys and colour coded advance springs (see pictures below). These are $32, so very reasonable.

There is an in depth article on the removal of the old dizzy, so I won't go through it here, but the new dizzy is much easier to replace the advance springs than the old one.

I started by deciding how much total mechanical advance I wanted (I was going to go for 36 degrees to see if the engine would take it, but 34 degrees seems to be as much as I can give it before pinking sets in on Unleaded petrol. 36 degrees may be possible on Super (Premium Pump Gas) Unleaded, but not on Unleaded (Pump Gas) with an aggressive advance curve).

I then decided on what rate of advance I required. As I already had the Mopar Performance advance springs fitted, I went for the fastest rate I could get.

Part of the advance curve fit includes charts to show the various advance curves available, and what spring combinations are required (I went for 2 x Pink springs)

I next decided I wanted 14 degrees of static advance, so 34 minus 14 = 20, so I used the 20 degree key to setup the amount of total advance. (see picture below)

 

I had previously been running 18 degrees of static advance, and found 14 degrees a little flat in comparison, so I will be re-setting the advance with the with the 16 degree key so I can have 18 degrees static, and 34 total (18 + 16 = 34)

For little more than the cost of a new standard dizzy, you can add this adjustable dizzy which will allow you to adjust your ignition to give the best results on modern fuels with these old design of engine, especially the older 383 and SP engines which require 5 star high octane petrol.

When I settle on my final figures I will update this article, but as all engines and quality of petrol is individual, you will need to find your own optimum settings.

Enjoy the ride!