How does a new carb interfere with the stock distributor

[Anonymous]

OK, I know this might have been answered somwhere else, and if so please directme there, but otherwise my question is: If I want to switch the stock autolite 1100 for something 2bbl-ish, do I also need to switch the distributor if I still have the stock 65' vaccum advanced one?

 

[66200i6]

Do a search for any of the following: 5200, DGV, DFV, DizzyII. Most of these discussions include why going to one or the other alone can create timing advance problems.

Good luck, Ric.

 

[CZLN6]

Howdy:

I'm assuming that you are dealing with a '65 vintage setup. The stock distributor is a Load-a-Matic that is designed to work in harmony with the '65 Autolite 1100 with a Spark Control Valve in place. The Spark Control Valve sends a very specific, load sensitive vacuum signal to the distributor. If you change either the carb to one without the SCV, or the distributor to something other than a Load-a-Matic, it will not work as designed.

Many adaptations have been tried an work sorta, but not perfectly. Take a look at the sticky at the top of this forum for more exact details of function.

Adios, David

 

[Anonymous]

What I was thinking was to switch to a holley 2300, and from what I'm reading here, it doesn't look like this carb has vaccum advance port, so if I understand correctly, I would have to swich distributors to duraspark II unit. If this is not so, can someone correct me?

 

[Inline6Merc]

So how would you run multiple carbs? I have both autolite 1100, do i just hook one up to it?

Later,

Curtis

 

[CZLN6]

Howdy Back BGTBNGR:

Yes, the holley 2300 does not has a Spark Control Valve (SCV). It does have a ported vacuum source and a full vacuum source.

Your best bet is to upgrade your distributor to a '68 or later, which will have a ported vacuum advance (Compatible with the Holley) and mechanical advance built it. These distributors can be upgraded to a "Pointless" electronic system called PetroniX, or you could move up to the later DuraSpark II electronic ignition system.

Adios, David

 

[66 Fastback]

Curtis, I doubt that hooking up the stock Loadamatic distributor to just one of the carbs on a dual carb setup is going to work properly. If it has prograssive linkage it might work OK until the other carb starts opening. At some point, the flow is going to be shared by the two carbs. As a result, the vacuum signal to the spark control valve is going to be different/lower than if the engine was only operating on one carb. If you were to keep, the Loadamatic, you would probably have to adjust the advance mechanism somehow, and the you have limited adjustability on this distributor given that there is not centrifugal advance.
Just my humble opinion
Doug

 

[mugsy]

Look into your Shop Manual but I *think* the Load-O-Matic runs on 0-5 inches of Hg. Your car should idles around 19 inches Hg. And if you hook the LOM dizzy to a "ported" source I bet the vacuum will still be greater than 5 in Hg or hit the 5 inch Hg mark too quickly. So the dizzy will go to full advance basically all the time. Not good. The SCV vacuum and "ported" vacuum are not the same thing.

Mugsy

 

[Anonymous]

Thanks for the info CZLN6, I thought somehting like that might work, but wasn't for sure, and I actually have the pertronix in already, now I'll just have to see whether its swappable.