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What is oem carb? |
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Deacon
AMC Fan Joined: Jan/13/2021 Location: Everett, WA Status: Offline Points: 6 |
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Posted: Jan/16/2021 at 9:17pm |
Inherited a 74 Javelin with 360 4bbl Holly. I have done research, but still have questions. Is it the OEM carb? Does anyone happen to know what model of Holley. I don't want to change it, just be able to adjust it properly. Thanks
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6762 |
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Most likely a dealer/owner replacement.
On the horn (top) of the carburetor will be a "List-xxxx" #. This will provide you with everything to research the carburetor. In the day it was common for a dealer to replace the Motorcraft carburetor with a Holley. They had a good reputation, more technical support, and the average garage mechanic of the day could tune a Holley vs the Motorcraft. AMC even lists Holley's that were acceptable as dealer installations in prior years. A well functioning Motorcraft is a fine carburetor. Many just gave up on them as they didn't understand how to tune them, or just didn't like them.
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ccowx
AMC Addicted Joined: Nov/03/2010 Location: Yukon Status: Offline Points: 3510 |
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Just to be clear, the Holley is not stock or oem on the car, though it may have been considered a legitimate replacement by the factory, as Trader says. It was common as dirt to replace the factory carb with something else, either a Holley or a Carter. One other thing to check that might give you some idea of whether this carb was put on back in the day or years later is the date code, also likely on the air horn of the Holley.
Chris
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CamJam
Moderator Group Joined: Jan/04/2014 Location: Arizona Status: Offline Points: 6479 |
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I believe the original carb would have been a Motorcraft 4300.
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'73 Javelin 360 (current project)
'72 Baja Bronze Javelin SST '69 Big Bad Orange AMX (2018 Teague Heritage Award) SOLD |
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scott
AMC Addicted Joined: Jul/10/2007 Location: Wildwood Pa. Status: Offline Points: 3498 |
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We would need your VIN # to determine what the original carb was on your 1974 Javelin. It could have been either a 2 or 4 barrel Motorcraft. As Cam mentioned, if a 4 V originally it would have been a 4300. If originally a 2 V, it would have been a 2100 Motorcraft. Then there were different versions of those carbs depending on the transmission. I doubt the factory would endorse the use of a Holley back in 1974 for anything other than off road use only, such as performance use. They wouldn't want to run afoul of the tightening Federal emissions regulations. Yes, they showed a Holley in the Group 19 performance parts catalog, but by the mid 70's were they available, & would the factory suggest using them on a street car? To tune the Holley for your Javelin, look for one of the Holley carb tuning books out there, & follow their instructions.
Edited by scott - Jan/17/2021 at 5:19am |
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Deacon
AMC Fan Joined: Jan/13/2021 Location: Everett, WA Status: Offline Points: 6 |
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Thanks for your feedback. The vin does show that it is a 360 4V car. I just wasn't sure what was OEM. On to tuning the Holly. It's running very rich.....
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mmaher94087
AMC Addicted Joined: Apr/01/2008 Location: Arizona Status: Offline Points: 1676 |
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Sounds like a blown Power Valve. Easy to replace. Common problem.
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Mike
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ramblinrev
Moderator Group Joined: Dec/28/2008 Location: Wisconsin Status: Offline Points: 11472 |
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Factory carb would be the Motorcraft 4300 with an 4TA4 tag (automatic) 4TM4 tag (manual).
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74 Hornet Hatchback X twins (since 1977)
62 American Convertible (still worth the $50 I spent in 1973!) AMCRC #513, AMO #384 70 AMX 360 4-speed (since 1981) |
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PHAT69AMX
AMC Addicted Joined: Jul/07/2007 Location: West Virginia Status: Online Points: 5905 |
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1973 AMC 401 AutoLite 4300 for reference
360 very similar. What is stamped on the choke horn of the Holley? A simple test to see if the Power Valve is bad is to screw the 2 idle mixture screws all the way in and lightly seat them, usually it will keep idling that way if the power valve is bad or it will quit if the power valve is good. High fuel pressure, high float setting, or bad needle and seat or needle and seat o-rings are other possible causes, as well as secondary idle speed screw closed to far and primary idle speed screw opened too far which over exposes the primary transfer slots causing a loss of control of the idle mixture by way of the idle mixture screws. |
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