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Discussion Starter #1
Hi all,
Newbie here,
I just bought (last Fall) a 1966 Mustang sedan with a 200 cu inch 6 Cyl motor.
The carb that's on it is a Weber 15709.
My buddy, who is more tech-savvy than I am, keeps saying that this is the wrong carb, too big and that the correct carb would let it idle better.
Any thoughts on this??? Thanx!!!! JP
 

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How about some pix? IIRC, way back when, Weber did offer rebuilt Autolite 1100's. Also could use a pix of your distributor guts, from the top, with the cap and rotor removed. This will tell us if it has the "Load-O-Matic" distributor which requires a matching carburetor with SCV (Spark Control Valve).
 

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The pretty pics are from a restored 1966 Sprint 200 (I think @NEFaurora posted these a few years ago). I think these are Autolite 1100's.

The not so pretty pics are mine, which is a Holley 1940.
 

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The Original carb to a 1965-1966 Mustang 6 cylinder engine would be a "NON-IMCO" (Non Emissions)...closed system, SCV (Spark Control Valve) Autolite 1100 1v (1 Venturi) carb. It would be the last two pics shown above on the "Restored" Sprint 200 engine.

Yes, You'll have to post some pics of your Carb setup and your distributor before we can diagnose any further..

:eek:)

Tony K.
 

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Discussion Starter #7
Sorry for the delay; I was away for a wedding and have been sick since. Here's too many views of the carb and one of the distributor.
Thanx!!!!!
 

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Well, that's DEFINITELY a Weber and DEFINITELY a Load-O-Matic distributor. Both incompatible with each other. The LOM has no mechanical spark advance, it's purely vacuum operated and NOT manifold vacuum. The maximum vacuum signal to the distributor is intended to be around 4"hg, courtesy of the carburetors internal vacuum circuit and Spark Control Valve. The Weber is going to send a full manifold vacuum signal to that distributor, the result being you'll effectively have your spark advance locked at maximum.

The solutions available are to replace the Weber with the correct Autolite 1100 unit or to replace the distributor with a non-LOM unit (and non-IMCO unit, as well).
 

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Yes, However nice....Definitely incompatible with his Disty..... Guess that he could go one of two ways here....Either upgrade the Disty..or downgrade the carb to the Original "NON-IMCO" (Non Emissions)...Open system, SCV (Spark Control Valve) Autolite 1100 1v (1 Venturi) carb.


I am also correcting myself per se here..Earlier above, I said that the The Original carb to a 1965-1966 Mustang 6 cylinder engine would be a "NON-IMCO" (Non Emissions)...closed system, SCV (Spark Control Valve) Autolite 1100 1v (1 Venturi) carb. It's only a "Closed System" for CA cars only. All Non-CA cars were "Open System" engines...until the IMCO (IMproved COmbustion) Emissions engines came in... - in Mid to Late 1967...when all engines became IMCO (IMproved COmbustion) Emissions Controlled engines...then all engines produced were a "Closed System".

:eek:)

Tony K.
 

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Your dizzy has no mechanical advance, and no normal spark advance. It has to work with a 'weirdo' 1V Autolite Load-O-Matic carb that adjusts spark advance using a special vacuum unit. They were not performance parts.

With a distributor that DOES have vac (and mechanical!) advance, your car will run a lot better. Your carb is a 2V, but with the adapter and intake you've got on your 200, I don't expect it would actually run any better than a standard 1V Autolite.

The Load-O-Matic system has to have both the special carb AND dizzy to work right. You can't mix and match. With no functional spark advance, that poor thing is going to run awful, and have no guts at all. An I6 Mustang is not going to roll your socks up and down when you step on the gas anyway, but when they work right, at least they are fun to drive.

Driving a slow car fast is always fun. =)
 

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Yes, However nice....Definitely incompatible with his Disty..... Guess that he could go one of two ways here....Either upgrade the Disty..or downgrade the carb to the Original "NON-IMCO" (Non Emissions)...Open system, SCV (Spark Control Valve) Autolite 1100 1v (1 Venturi) carb.


I am also correcting myself per se here..Earlier above, I said that the The Original carb to a 1965-1966 Mustang 6 cylinder engine would be a "NON-IMCO" (Non Emissions)...closed system, SCV (Spark Control Valve) Autolite 1100 1v (1 Venturi) carb. It's only a "Closed System" for CA cars only. All Non-CA cars were "Open System" engines...until the IMCO (IMproved COmbustion) Emissions engines came in... - in Mid to Late 1967...when all engines became IMCO (IMproved COmbustion) Emissions Controlled engines...then all engines produced were a "Closed System".

:eek:)

Tony K.
Tony, what’s the physical difference between an open and closed system carb?
 

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Keep the weber, upgrade your distributor to a duraspark from a 76 fairmont with a 200/6 cylinder. Get the duraspark box, make your own harness, and now you have electronic ignition!
 

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Coupster has it right. I converted to that combo and it runs great now. When all of the ford six fans say something from the factory is junk that should tell you something. Go to this site https://www.vintageinlines.com/. They have a tech section that is amazing and will show in detail how to do the wiring. I also highly recommend the ford falcon six performance handbook from vintage inlines.
 

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The cheap easy solution is to go to the Advance auto website and order a 1968 Mustang reman distributor, check nearby stores and see who has it in stock. Order online/pickup in store.

Its a $100 with a core deposit less the 25% online discount, so it costs you $75 + tax. Cap and rotor not included.
 

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"Tony, what’s the physical difference between an open and closed system carb?"

An easy answer would be "SCV" (Spark Control Valve).....but that's not necessarily always the case since '65-Early '67" California (CA Built San Jose cars) used SCV's on their carbs until late '67 when ALL cars went to IMCO engines. The much better answer is that it all has to do with the car's PCV system on the engine. CA San Jose Cars used a "CLOSED" PCV system..(Extra nipple and hose on the Aircleaners)..where as '65-Early '67 engines had a somewhat more "OPEN" system, but in reality it was only really Partially Open. A Real "OPEN" System engine example would be a '64 1/2 engine that has a Road Draft Tube....since it's All open... Absolutely no containment of the engine gases and no real re-circulation of gases..

:eek:)

Tony K.
 

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The cheap easy solution is to go to the Advance auto website and order a 1968 Mustang reman distributor, check nearby stores and see who has it in stock. Order online/pickup in store.

Its a $100 with a core deposit less the 25% online discount, so it costs you $75 + tax. Cap and rotor not included.
So for my Clint Eastwood reference:
For a few dollars more...
You can do the duraspark

Buy a second trailer plug extension that is the length you need. Cut the short one in half. Put one end on distributor, the other end on spark box. Use longer extension to connect them. You may need a new cap too!

https://www.oreillyauto.com/shop/b/ignition---tune-up-16776/distributor-12503/8c7c95368caf/1978/ford/fairmont?q=distributor

https://www.oreillyauto.com/detail/b/masterpro-ignition-4513/lighting---electrical-16777/modules-coils-25074/ignition-module-control-unit-ignitor-12521/e281cd9fff15/masterpro-ignition-6-terminal-ignition-control-module/27053/4598841/1978/ford/fairmont?pos=0

https://www.oreillyauto.com/detail/b/towing-solutions-3935/agriculture-hd-parts---accessories-19818/fleet---heavy-duty-20088/trailer-plugs---brakes-20099/2-3-4-5-way-flat-connectors--wiring---accessories-18813/6dc2f0216a2d/hopkins-towing-solutions-wire-adapter/48145/4379658/1978/ford/fairmont?q=Trailer+plug+extension&pos=0
 

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Also, go to vintage inlines and buy an aircleaner adapter so you can run a proper aircleaner on the carb and get rid of that ugly rectangle thing.
 

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Discussion Starter #19
The cheap easy solution is to go to the Advance auto website and order a 1968 Mustang reman distributor, check nearby stores and see who has it in stock. Order online/pickup in store.

Its a $100 with a core deposit less the 25% online discount, so it costs you $75 + tax. Cap and rotor not included.
Why a '68?? JP
 
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