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Author
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Topic: 1985 gt vacuum diagram
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timbostang
Journeyman Posts: 2
From: maysville,ky,usa
Registered: Sep 2005
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posted 09-26-2005 08:45 PM
 
i recently traded for a 85 gt that is carburated with a holley double i dont know what cfm and i need a vacuum schematic so i can get he brakes working and the idle set can anyone help
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1986MUTANGGTCONV
Journeyman Posts: 48
From: NJ
Registered: Sep 2005
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posted 09-27-2005 05:13 PM
oh no that 85 was a quadrajet very good carb. u may have just traded for a p.o.s. holley why else would they trade? any way if you want a better carb than the one you now have or had better get a brand new holly 650 speed demon..
but hey w.t.h. slap it on and see for yourself if you made a bad trade. i bet you did.
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timbostang
Journeyman Posts: 2
From: maysville,ky,usa
Registered: Sep 2005
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posted 09-27-2005 08:49 PM
i didnt trade for the carb i traded for the car and the carb is stock looks like a holleythough im not sure the car was ordered from ford with the 4 barrell double and the original owner doesnt know how to get the vacuum line on right im new to mustangs and fords so im a liitle lost
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TurboGT
Gearhead Posts: 318
From: Hutchinson, Kansas
Registered: Mar 2002
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posted 09-28-2005 12:28 PM
The factory carb on an '85 GT 5-speed was the Holley 4180 series. It's a 585 CFM vacuum secondary unit. As for schematics, have you tried your local public library? I've gone there for many a wiring diagram, vacuum diagram, repair info, etc. They have a very nice online system of repair info. ------------------
Mark Walton '83 Mustang GT 2.3 Turbo NHRA SS/O
'69 "off brand" NHRA SS/EA
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Daniel Jones
Gearhead Posts: 972
From: St. Louis, MO
Registered: Aug 99
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posted 09-28-2005 12:48 PM
> oh no that 85 was a quadrajet very good carb. u may have just traded for
> a p.o.s. holley why else would they trade? The 1983 to 1985 Mustang 5.0L HO's used Holley 4180 carbs, not Rochester
Quadrajets. The 4180 is similar to the 4160 series but was specially
developed by Ford to meet emissions without any electronic aids. It cannot
be duplicated with a regular 4160. The metering block is very different
and the emulsion tubes, air bleeds and other stuff are done properly
(better than normal Holleys). IIRC, it was rated at 585 or 595 CFM and used
annular boosters on all four corners, a dashpot for throttle control during
deceleration, vapor vent equipped fuel bowls, side hung floats, a specific
fuel inlet and a two stage power valve. The 4180 also has "close limit"
main jets with tighter tolerances for emissions purposes. Be aware there are no idle mixture screws in the primary metering block,
unlike 4150/4160 Holleys. Instead, there is an idle mixture screw for
each barrel, however they are in the base plate and are sealed to prevent
tampering. You can drill a small hole in the bottom of the base plate for
each mixture screw and pick out the plug to provides access to the mixture
screws with a small Allen key. There is also no idle speed screw in the
base plate. Instead idle speed is set with the dashpot. The secondary
metering plate is different than a 4160 in shape, so they don`t interchange.
The carbs are worth much to most people so you can usually pick them up
cheap at swap meets if you want to experiment or need spare parts. Hot Rod Magazine did an article on the carb in June 1986 called "Family Ties"
that compares the Ford / Holley 4180 to the generic Holley 4160 600 CFM vacuum
secondary carburetor. It has info on how to modify the carb with a metering
block and jets for the secondaries and talks about other tricks. You can
download the article here: http://www.swcp.com/~dilts/mustangs/holley_4180/index.html Dan Jones
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ChitownEd
Journeyman Posts: 15
From: Chicago, Il. usa
Registered: Mar 2005
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posted 09-30-2005 06:53 PM
I had an '85 GT with the carb you speak of. I had no problems with it. I know there was an artice a while back in 5.0 Mustang of a carb shop, I believe in California, that did some modifications of this carb. It was almost like turning the carb into a smaller version of a 3310 vac-sec carb. You may be able to look it up. I did the mods to my carb, and it never game me a problem. It may especially work in KY where some counties are emissions exempt.
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