Author Topic: 68 390gt manual carb?  (Read 926 times)

Offline adam8888d

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68 390gt manual carb?
« on: August 27, 2022, 01:21:20 PM »
You have just gone out and bought yourself an early 68 mustang 390gt manual shift. The engine is running a little ropy. You know its the carb and despite on trolling the internet for an original. You decide to go to Holley as they provided the carb in the first place. Your engine has had mild up grade. Headers. Pertronix internal electronic ignition a long with an edelbrock inlet manifold that can all be put back to stock in time keeping the twin vacuum distributor. You are wanting to keep the carb in keeping with the period correct original one.

What carburettor do you decide to purchase from Holley?

Offline carlite65

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Re: 68 390gt manual carb?
« Reply #1 on: August 27, 2022, 02:18:51 PM »
we cannot  recommend a course of action here due to the fact that this forum focuses on factory assembly line correctness. would suggest you pose the question over on vintage mustang forum as those guys are all over the modification scene. good luck with your endeavor.
5F09C331248

Offline adam8888d

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Re: 68 390gt manual carb?
« Reply #2 on: August 27, 2022, 04:50:50 PM »
Maybe I should park the car in hope the  original carb that was removed tuns up on eBay some day.

Offline J_Speegle

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Re: 68 390gt manual carb?
« Reply #3 on: August 27, 2022, 05:55:16 PM »
Don't think that is necessary. You've already choose a current path for your car with the current modifications.  It's just that this is not the best forum to get you the best information your current question considering the other options - and other forums
Jeff Speegle

Anything worth doing is worth doing concours ;)

Offline adam8888d

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Re: 68 390gt manual carb?
« Reply #4 on: August 27, 2022, 07:22:39 PM »
I understand what you are saying. All the other items I mentioned seem to be quite easy to replace back to stock. I have been told it?s more of a lottery win getting the correct carb. I could do with a temporary substitute until the time comes rather than having an ornament . Regards

Offline RoyceP

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Re: 68 390gt manual carb?
« Reply #5 on: August 27, 2022, 08:00:37 PM »
More likely the carb needs to be gone through, or you have a non - carburetor issue like the distributor being worn out, the Pertronix going south, a bad coil etc. Generally the stock carburetor is very forgiving of all the mods you mention and a lot more. So often unknowing folks blame all manner of trouble on the carburetor.
1968 W code 427 Cougar XR-7 GTE Feb 23 Dearborn C6 / 3.50 open
1968 R code 428CJ Cougar XR-7 May 13 Dearborn C6 / 3.91 T - Lock

Offline hopey

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Re: 68 390gt manual carb?
« Reply #6 on: August 27, 2022, 11:14:57 PM »
You have just gone out and bought yourself an early 68 mustang 390gt manual shift. The engine is running a little ropy. You know its the carb and despite on trolling the internet for an original. You decide to go to Holley as they provided the carb in the first place. Your engine has had mild up grade. Headers. Pertronix internal electronic ignition a long with an edelbrock inlet manifold that can all be put back to stock in time keeping the twin vacuum distributor. You are wanting to keep the carb in keeping with the period correct original one.

What carburettor do you decide to purchase from Holley?

I wouldnt buy anything new from Holley. Personally Id contact someone like Drew at AirFuelSpark. He specializes in restoring & rebuilding only vintage Ford Holley carbs. If he cant sort you out with a concours original he can build /recommend you something that will run way better and be as close to authentic as possible rather than any off the shelf offering from Holley. Just a warning - he does have an obsession for FE engines and 4x2 setups.

https://www.afscarbs.com/



« Last Edit: August 27, 2022, 11:44:13 PM by hopey »
1970 BOSS 302
Built 11/15/69 Dearborn

Offline rnegless

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Re: 68 390gt manual carb?
« Reply #7 on: August 28, 2022, 10:24:56 AM »
My C8OF-C had a worn secondary throttle shaft. I sent it to a reputable service in for rebuild and they did everything but fix the worn shaft.  While the carb was out at the shop I put a Holley Street avenger on and it ran good.  I thought of putting my bowls and cross over tube on the Avenger to give it a stock appearance but ended up replacing the throttle plate on my C8OF-c and that fixed my problem.  You can check for a vacuum leak at the shaft with a spray of carb cleaner. Good Luck
« Last Edit: August 28, 2022, 12:40:17 PM by carlite65 »
68 San Jose 390 GT 4sp 3:25 Decor 12/29/67

Offline Drew Pojedinec

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Re: 68 390gt manual carb?
« Reply #8 on: September 02, 2022, 07:10:02 PM »
I wouldnt buy anything new from Holley. Personally Id contact someone like Drew at AirFuelSpark. He specializes in restoring & rebuilding only vintage Ford Holley carbs. If he cant sort you out with a concours original he can build /recommend you something that will run way better and be as close to authentic as possible rather than any off the shelf offering from Holley. Just a warning - he does have an obsession for FE engines and 4x2 setups.

https://www.afscarbs.com/

The problem is?. For a 67 or 68 390 carb, I wouldn?t suggest using a 67-68 carb if the engine is modified.
These particular carbs (67-69 GT 390) are pretty darn specific to the engine.
From his description, I?d suggest an old school 3310 or a 650 double pumper.

I love putting the original parts on original engines, but this is the one exception where it generally goes badly.

To the original poster, I?m sorry I don?t have a suggestion about a new carb, I simply don?t deal with them enough to make an educated guess there.

Dp