Distributor recommendations?

[Richard2112]

Originally Posted by 72SB

There is a guy, David Ray, who rebuilds dizzys. He may be retired now but I have his write up saved. What is the most ignored provision of a dizzy is the vacuum advance and controlling when it comes in and how much advance it does provide is a critical factor be it points, or HEI dizzy to control.

Crane "did" make a VA and stop plate kit which I did buy and install on my Camaro a few years ago. They are now extinct. In dialing in the tune of my new 357 crate motor I found it critical to have dizzy set up right, which beyond timing, is critical on VA function and after installing the detent plate and making the adjustments using alan key on VA and setting timing I was then ready to proceed making the various adjustments (metering rods, step up springs, jets) on my carb. All of this was a multi-step process, but man once done the drivability and performance is great.

For any street car, if your VA is not connected do so.

Here is a pic of my VA with detent plate installed and the alan wrench used to djust VA. Home made versions are also done.

That is some interesting information. It is indeed my plan to get the timing established as I recognize it's authority in making power and dependability.

I have just never been down the road of building a strong distributor before. In the past I've yanked one out, stabbed another in, gave it a turn with a timing light and off I went. To me, it has been similar to changing an alternator or a starter, the need to rebuild the unit never inspired me. But now things are different. Given the many changes my 383 build has imposed, there is going to be a need to set up an ignition system specific to my build. I can no long rely upon "one size fits all" generic components. Every feature of my distributor is under careful consideration and even things I hadn't considered. One thing I have recently had to consider is that some aftermarket dizzy's are entirely proprietary and should I have a problem with it on the road, it could be an expensive trip home!

I am goin to pay attention to the vac advance, the mechanical advance, how much and how soon, plus the module, coil, cap, rotor and drive gear.

There are two things I have been looking for and one is information on the magnetic pickup. Many sources seem to confuse this with the module so instead of info on the mag pickup, I get another article on changing the module.

That is also true when I search for information on the removal, testing and install of the pickup. I understand there is a c-clip which needs to be removed (I guess I'll find it) to remove/replace the mag pickup.

I have many things to learn about this and sure appreciate the information from those who have traveled this road.

I may be overthinking it but rather that than to let some detail slip that makes all the difference between a great ignition and a mediocre one.

Thanks for the info with pics.

[72SB]

The MSD ready to run I noted in an earlier response should fit your needs well. A Timing light and tach will tell you when and how much advance the VA is providing with and without vacuum. Plugging the VA will tell you how much mechanical timing it provides. A spring and weight kit (although for your use I doubt you would need that) is available to fine tune more for drag race use (full timing comes in sooner)

If you find you want to limit the amount of vacuum advance than what GM did originally was put a piece of vacuum line on the small leg of the VA to limit its travel thus the amount of vacuum advance (read not the mechanical) it brings in

As I noted earlier you want a combined total of 20-24 degrees at idle. If your dizzy does in fact introduce "vacuum" advance at that low of a rpm (about 750-850 rpm) than you want to limit that to around 10-12 degrees introduced with 10-12 of base timing (vacuum plugged) at idle to get 24 degrees. You generally want full timing 0f 34-36 degrees at about 3k rpm. If you want that in earlier than you introduce lighter springs to allow that

[Tomchev]

We have ran the cheap HEI and the higher dollar ones in a circle track car and can not tell in difference in them

[Richard2112]

I have just received my F.A.S.T 303051 distributor and I'm (naturally) taking it apart and looking things over. To their credit it was well packaged and the unit looks good (so far). It also came with a vac limiter cam and sets of springs. Cool.

I had the impression though that there would be some numbers on the vac advance and the centrifugal weights which would identify some helpful characteristics. For example, how much advance will the weights add when all in? Or, what is the max advance of the vac pot?

I can figure these things out but I assumed some info would be provided with the unit. I can pull a vacuum at the pot with a hand pump but was hoping for graph that indicates say, 2 clockwise turns of adjustment screw equals X degrees of advance at Y inches Vac. 4 clockwise turns.... and so on.

I tend to over think these things so maybe that's what I'm doing now.

[72SB]

Its trial and error on weights and springs using a timing light. Ideally your damper is fully etched, or you have the MSD timing mark tape on yours to be able to read each degree.

My detent plate is on the 5th notch but again, you need to see how much base and vacuum advance you get using a timing light and make adjustments from there

This is what came with my Crane adjustable VA kit. IDK if it applies to your brand. I wound up 1 3/4 turns on my VA adjustment using the alan key.