Vacuum Source when changing to Duraspark

salty_monk

Well-known member
Am I right in that I can use the vacuum source that's tapped into the spacer plate & currently runs to the wipers? I planned to put a T in it & run to the vacuum advance as well as the wipers. I figure worst case the wipers will pull the vacuum away from the advancer when running so MPG may drop a bit.... not needed to use the wipers yet though in a few months of ownership (So Cal so rarely need them).

I then believe I have to plug the Vacuum source for the Loadomatic on the holley carb? I plan to cut short & crimp & possibly solder or expoxy the metal tube currently connecting it to the distributor vac unit. (Carb end)

Anyone see anything wrong with this?

By the way I have a spare AUTOLITE 1100 carb from a 250 that I'd like to use... it's rebuilt but not sure what jets are in it. What jets should be in there for my 200ci? Is it better to use this than the single barrel holley on there right now? It has a thermocouple type choke so I guess I'd probably lose the choke (right now I have a manual but often don't need it) unless anyone knows a good way to make it work..... The linkage appears as if it will fit right up etc.

Thanks in advance,

Dan :)
 
You are probably in the experimental realm as far as vac source to see which works the best.

For example, on my 300 I recently changed back to the original carb I started with and there is no significant difference between running manifold vac or off the timed port in the carb base. Running off manifold vac I get a wee bit more advance at idle and a little different carb idle adjustment. The carb I just removed only had one vac fitting on the carb body and ran like crap using it for a source unless I opened the throttle plates a bit with the idle speed adjustment so I plumbed in to the manifold directly and it ran fine. Pretty much a trial process to determine what an engine likes.
 
Vacuum wipers? What car do you have? I can tell you that my 66 Mus w/ automatic had NO extra ports for vacuum on the carb or base. However, there is a square brass fitting on the side of the intake manifold with three ports, of which two are blocked off. My distributor runs off of this one and I am told that this is the stock vacuum source for timing advance.

I still have two ports left. One for power brakes I guess and one for something else like a vacuum gauge in the cockpit to meter fuel use, like a car in the Mobil Economy Run.
 
If it is a 69 head, you should have a threaded bung just below the carb mount on the intake manifold on the fender side. Put a threaded fitting with one or more vac nipples in there. Either salvage one from a yard or find a new one at a parts store. This is where you should get your advance vacuum from.
 
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