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MSD Pro-Billet Distributors Install

It happens to all of us, we see a great new product, know that we need it, only to find out that the company doesn’t make it for our application! Well this has been the case with the new line of MSD Pro-Billet Distributors for a few years now. Our project Jeep has always run a stock, auto-parts store, el-cheapo distributor. With all of the other high-zoot ignition accessories we have added (coil, MSD Ignition system, 8 mm plug wires, etc.) it has never really benefited fully, because no hi-quality after market distributor was available for the Jeep 258 engine. I guess all my complaining to MSD year after year at the SEMA show finally paid off. I like to think that they built the new line of Pro-Billet distributors for the 258 just for me. Probably not the case, but hey I like to feel important.

The new lines of Pro-Billet distributors are available for the following AMC engines, 258, 290, 304,343, 360, 390, and the 401. The Distributor begins life as a chunk of 6061-T6 aluminum before being CNC-machined to precise dimensions. The sturdy, flex-free housing is fitted with a sealed ball bearing and a long-sintered bushing for high rpm accuracy. An oversized steel shaft receives a Tuftride coating to reduce friction and prevent corrosion. MSD’s race proven magnetic pickup supplies a trigger signal that is accurate to within one degree at any rpm. The pickup is maintenance-free and mounted above it is a fully adjustable mechanical advance assembly. This advance is easy to adjust and is supplied with different springs and stop bushings or can be locked out completely. For street cruising economy there is a vacuum advance canister, but if you’re not concerned with economy, the canister can also be removed and locked out. The Pro-Billet MSD AMC Distributor is supplied with a Racing Rotor and heavy-duty alkyd cap with brass terminals. It must be used with an MSD 6, 7, 8 or 10 Series Ignition.

Installation of the distributor is simple, it is basically a “remove and replace” with a few simple and important steps. Before you remove your stock distributor, mark the direction the rotor is pointing so you can install the new one in the same direction. Also make sure you know the firing order for your engine and know which plug wire was which before you go yanking them all off. We do this by placing tabs of masking tape on each plug wire and marking the order there.

Once these two steps are out of the way, simply remove your old one, install the MSD, put the new cap on, hook your plug wires back up in the right order and your all set. Along with the new Distributor we also installed a set of MSD 8mm Plug wires to make sure we were making full use of the spark now produced.

MSD provides a chart in the instruction manual to explain what the different springs and stop bushings included with distributor will do. The distributor was factory set with the middle-of-the-road springs and bushings in it.  MSD does this to give you a starting point for tuning your distributor to fit your specific needs. Choosing to leave the springs and bushings in their initial settings, we opted for a few more degrees of timing, which was impossible with the old junker of a distributor.

The next test drive showed a noticeable difference, it had quicker, crisper acceleration. What the heck, lets give it another degree or two and see what happens. Sure enough advancing our timing 4 degrees beyond stock, the little motor was finally starting to feel strong. Here of course is where the trouble usually starts when you fool with timing. It you advance too much you get really hard starts when the motor is at operating temperature, and you may start to get predetination in the cylinders. I was pleasantly surprised, none of that happened. The Jeep starts quickly at all temperatures, runs great, and has more power than ever before. I have yet to change the advance springs and stop bushing from the mid setting. Eventually I may just to see what happens, but for now the little 258 seems to run great.

General Information

Billet Housing
Like the multiple spark, CD ignition, MSD was the first to introduce a distributor housing machined from a billet of aluminum. MSD uses state-of-the-art Computerized Numerical Controlled (CNC) mills and lathes to create each housing. This procedure produces a flawless, lightweight distributor housing that is accurate to within 0.001″.

Shaft and Ball Bearing Guide
The complete line of MSD Distributors uses a polished steel shaft that receives a QPQ, or Tuftride coating. This process produces a durable finish that reduces friction and resists corrosion. To accurately guide this shaft, MSD uses a sealed ball bearing located at the top of the housing. At the bottom of the housing, an extra long sintered bushing controls the shaft. This combination keeps the shaft spinning smooth and accurately throughout 10,000+ rpm.

Magnetic Pickup
All of the MSD Distributors (except crank trigger models) use a high output magnetic pickup to trigger the ignition system . This pickup is completely maintenance-free requiring no adjustment ever. The pickup is mounted to the base of the distributor housing and plugs directly into your MSD Ignition Control. A trigger signal is created as a precision made reluctor (attached to the shaft) passes by. The reluctor has a “paddle” for each cylinder and when the paddle passes the pickup, a signal is created.

Adjustable Mechanical Advance
One of the most important features of the MSD Distributors is the adjustable mechanical advance assembly. The advance assembly allows you to accurately modify the advance curve to match your specific application. To start with, the advance plate is stamped and machined from chrome moly . Weight pins are then staked in and tig welded in place. This assembly, along with the weights, then receive a corrosion resistant QPQ coating. Nylon weight pads are installed under the weights to ensure smooth movement as the weights are pushed out from centrifugal force to advance the timing. The advance assembly is mounted on top of every MSD Distributor making adjustments a breeze. A variety of advance springs and stop bushings are supplied with each distributor giving you the ability to set up to 24 different curves.

CARB Approved Distributors
MSD offers four distributors for Chevrolet V8s that have been approved by CARB for use in all the states. Each distributor features a vacuum advance for street economy.

Most MSD Distributors must be used with an MSD Blaster Ignition, 6, 7, 8 or 10 Series Ignition Control. Only the Pro-Billet Ready-to-Run and Pro-Billet HEI Chevrolet models can be used without an MSD Ignition.

So if you are looking to upgrade the factory distributor on your AMC engine, log on to MSD’s website and find the dealer nearest you. It will definitely be worth the investment.


Description Notes Rating
Ease of Install For the most part, this is a “remove & replace” installation. After install is complete, you may have to tweak the timing and springs. This is also a one-wire plug in and requires the MSD boxes as described above.
Performance Easier starts and crisper throttle response were the two major items we’ve noticed. We also noticed about 1 to 2 m.p.g. increase in fuel efficiency.
Durability With the billet construction and the other quality manufacturing processes, this is probably the most durable and over-built distributor you can find. To date, water, mud, and dust have yet to cause a failure or any problems.
Appearance The billet shaft, shiny cap, MSD plug wires and the pre-built one-plug hookup makes for a super clean appearance.
Price in comparison to related products Compared to stock distributors, this is quite a bit more expensive. However, the limited supply of aftermarket, hi performance distributors for the 258 CID inline 6 cyl. is slim to say the least.
Tools Required Timing light, 1/2″ wrench, needle nose pliers and a flat-blade screwdriver.
Editors Notes This was a straight forward and simple installation that can be performed by just about anyone, even with limited mechanical experience. All that’s needed is a bit of patience to make sure you don’t get the timing off when R&R’ing the distributors. Overall we’d say that this is a great addition to your 258 engine…JC

MSD Ignition
12120 Esther Lama, Suite 114
El Paso, Texas 79936.
Email: msdtech@msdignition.com
Web Site: http://www.msdignition.com/

About Rick Webster

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