SAAC Forum

The Cars => 1968 Shelby GT350/500/500KR => Topic started by: Corey Bowcutt on March 19, 2020, 09:15:29 AM

Title: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 19, 2020, 09:15:29 AM
Soon I will be replacing the carburetor on my 1968 GT350 4 speed with an original carb.  Does anyone have any photos showing the correct plumbing for the original carb?  I can plumb things just like the carb that is in there now but I want to make sure it is correct.

Thank you, Corey
Title: Re: 68 GT350 Carburetor Plumbing
Post by: shelbydoug on March 19, 2020, 09:20:59 AM
You need to speak to the Coralsnake and specify Holley or Ford carb and for that matter, production line Ford or Holley or recall Holley.

I believe the Ford carb routing is considerably different then the Holley is.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 19, 2020, 10:01:16 AM
I actually bought the Carb from Pete.  It is the Holley carb I should have mentioned that.  I am looking for photos that clearly show how things are plumbed.

Corey
Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 19, 2020, 10:15:28 AM
Do you mean how does the fuel line route and vacuum hoses?  There isn't much more than that other than the choke tubes.

It's pretty much self-explanatory.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 19, 2020, 10:51:19 AM
I think he is looking for pictures of the choke tubes on the Holley version
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 19, 2020, 01:24:40 PM
(http://www.saacforum.com/gallery/8-190320132323.jpeg)
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 19, 2020, 01:27:35 PM
(http://www.saacforum.com/gallery/8-190320132357.jpeg)

Pictures provided by the great TLEA
Title: Re: 68 GT350 Carburetor Plumbing
Post by: shelbydoug on March 19, 2020, 01:48:42 PM
Quote from: CharlesTurner on March 19, 2020, 10:15:28 AM
Do you mean how does the fuel line route and vacuum hoses?  There isn't much more than that other than the choke tubes.

It's pretty much self-explanatory.

Oye-yei-yei! There he goes again! If it was self explanitory the carburetor could explain it itself? WTF? It's gotta' be me? Definitely me!  :o
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 19, 2020, 02:36:16 PM
Thank you Pete this is a good start.  Now I see 4 connections.  I can see where the large one goes to the PCV valve.  Can not see where the other three go to?
Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 19, 2020, 02:36:37 PM
Quote from: shelbydoug on March 19, 2020, 01:48:42 PM
Oye-yei-yei! There he goes again! If it was self explanitory the carburetor could explain it itself? WTF? It's gotta' be me? Definitely me!  :o

Just thought with pre-bent lines, there wouldn't be much variance in how things get routed. 
Title: Re: 68 GT350 Carburetor Plumbing
Post by: TLea on March 19, 2020, 03:28:14 PM
Quote from: Corey Bowcutt on March 19, 2020, 02:36:16 PM
Thank you Pete this is a good start.  Now I see 4 connections.  I can see where the large one goes to the PCV valve.  Can not see where the other three go to?
I thought you just needed choke tubes. I'll forward Pete other hose pics as well
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 19, 2020, 03:46:33 PM
The 4 hoses in Pete's pictures are exactly what I need.  The problem is I do not know where the other end of those hoses are going?  My car is obviously not correct right now because I believe they just have two of the hoses short circuited to one another (the hose with the white shield and the black hose going to the metal tube).  So I have no idea where the white hose and black hose going to the metal tube are supposed to go?  The third black hose I am guessing goes to the vacuum advance but not certain of that either?  The only hose I can see both ends out of the 4 hoses shown is the one to the PCV.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 19, 2020, 04:52:00 PM
There is no "white" hose. That is the insulation over the steel line. Those two steel lines from the carburetor go into the exhaust manifold. There is a press fit into the manifold.

The vacuum hose with the yellow stripe from the side of the carburetor goes to the vacuum tree on the thermostat housing.

(http://www.saacforum.com/gallery/8-190320171414.jpeg)
Title: Re: 68 GT350 Carburetor Plumbing
Post by: TLea on March 19, 2020, 05:15:03 PM
Hoses from rear block go to,
Tilt= larger hose w' green/white stripe
Vacuum tree and tee to distributor retard side=red stripe
smog cannister=black hose
I know you have a 4 speed so that's what I listed, auto different
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 20, 2020, 08:40:04 AM
Pete and Tim thank you so much for the help.  I am getting there but still have some questions. 

First I have headers so that explains why the PO just short circuited the two lines that run to the exhaust manifold.  I am sure mine is not the only 68 with headers is this what others have done, meaning just short circuiting these two ports?  Secondly I was thinking I could wrap the steel tubing around one of the header tubes and rout it to these two ports.  Is this hot air necessary for proper functioning of choke?

Second, Pete you said "The vacuum hose with the yellow stripe from the side of the carburetor goes to the vacuum tree on the thermostat housing" I am not familiar with a vacuum tree on the thermostat housing?  I show a picture below of my thermostat housing and there is no vacuum tree.  Should there be? I have a vacuum tree (shown in pictures) toward the back of the motor behind the carburetor.  Would I rout this hose to this tree?  You can see in the picture of my new original carb I do not have a fitting currently for this hose.  What happens if I do not have a hose connected here?

Tim, I am a bit confused about your directions.  You said "Vacuum tree and tee to distributor retard side=red stripe".  Are you saying that a vacuum line from my tree shown in pictures below run to the vacuum advance in the distributor?

I am assuming Tim all the hoses you describe are coming from the vacuum tree in the rear of the block I have pictured below is that correct?
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 20, 2020, 10:36:03 AM
The tilt hose looks correct.

You have the wrong thermostat housing

You should have a vacuum tree.

Your distributor vacuum advance should be a dual style, not the single type
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 20, 2020, 10:40:07 AM
You need to study this page:

http://www.thecoralsnake.com/GT350a

If you can not use the choke tubes because of headers, you can cap those two lines. I have used a vacuum cap on the tube. You can use a brass cap to close off the threaded connection

Once you start changing things ie., headers, it becomes slippery slope
Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 20, 2020, 11:08:20 AM
The choke 'chamber' on the exhaust manifold allows carb vacuum to pull hot air up into the thermostatic coil on the carb.  The thermostatic coil is how the choke/butterfly plate on the carb opens and closes.

With headers, it might be best to convert to a manual or electric choke.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 20, 2020, 11:10:35 AM
Thank you Pete.  I have been to your site one million times but there are still pages I have not seen and this is one of them.  This answers all the questions but does bring up one more for me.  I have electronic ignition so is the vacuum advance even needed at this point?

If anyone has the correct thermostat housing or vacuum advance let me know.

Thank you so much Pete
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 20, 2020, 11:13:44 AM
Thank you Charles.  I do have the electric choke off the carb that is on the car now that if worst comes to worst I can use I presume.  But that is why I was thinking about wrapping the metal tube around one of the header tubes so it would continue to draw hot air.  But this was just a wild thought.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 20, 2020, 11:39:07 AM
Two more questions occurred to me Pete.

1) does the cast iron thermostat housing with the tree work on the aluminum cobra intake manifold?

2) Do I need to have the hose going to the side of the carb that goes to this thermostat tree?  I currently do not have a fitting in the carb for the hose but I am sure I can get one somewhere.

Corey
Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 20, 2020, 11:39:23 AM
Quote from: Corey Bowcutt on March 20, 2020, 11:13:44 AM
Thank you Charles.  I do have the electric choke off the carb that is on the car now that if worst comes to worst I can use I presume.  But that is why I was thinking about wrapping the metal tube around one of the header tubes so it would continue to draw hot air.  But this was just a wild thought.

Without the vacuum draw, I don't believe the choke will work as designed... or at least be as effective, which will end up causing the carb to run rich.

Title: Re: 68 GT350 Carburetor Plumbing
Post by: The Troll Free Zone on March 20, 2020, 12:19:35 PM
Posted this on another thread for Milo, thought you might like to have a look.

(https://www.saac.com/forum/gallery/178-200320120559-45222146.jpeg)
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Special Ed on March 20, 2020, 12:41:20 PM
Chris in your photo the washer spacer goes on the inside of smog pump adjusting bracket bolt unless u have a/c then its not used.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 20, 2020, 12:56:12 PM
A small block is different and now we are off on a tangent...

The subject car is a 302.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: The Troll Free Zone on March 20, 2020, 12:58:40 PM
Thanks Ed. I think you or Bob might've mentioned that the first time around. I should explain this picture above and some other ones I posted on another thread were originally posted for all of you to critique before I installed the motor. There are more than likely a few errors in some of the photos.

Pete, sorry my bad I should've noticed that :-\
Title: Re: 68 GT350 Carburetor Plumbing
Post by: shelbydoug on March 20, 2020, 01:26:07 PM
Quote from: Chris Thauberger on March 20, 2020, 12:19:35 PM
Posted this on another thread for Milo, thought you might like to have a look.

(https://www.saac.com/forum/gallery/178-200320120559-45222146.jpeg)

My 302 doesn't look like that? I like all the striped hoses but I must have screwed up?
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Krelboyne on March 20, 2020, 04:12:21 PM
Quote from: shelbydoug on March 20, 2020, 01:26:07 PM
Quote from: Chris Thauberger on March 20, 2020, 12:19:35 PM
Posted this on another thread for Milo, thought you might like to have a look.

(https://www.saac.com/forum/gallery/178-200320120559-45222146.jpeg)

My 302 doesn't look like that? I like all the striped hoses but I must have screwed up?

No, they slipped in a GT-500 photo.   ::)
Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 20, 2020, 04:28:37 PM
Let's get us back on track here...  ;D ;D

Correct '68 GT350 4sp setup...
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 20, 2020, 04:32:58 PM
Thank you Charles
Title: Re: 68 GT350 Carburetor Plumbing
Post by: The Troll Free Zone on March 20, 2020, 04:43:11 PM
Quote from: Krelboyne on March 20, 2020, 04:12:21 PM
Quote from: shelbydoug on March 20, 2020, 01:26:07 PM
Quote from: Chris Thauberger on March 20, 2020, 12:19:35 PM
Posted this on another thread for Milo, thought you might like to have a look.

(https://www.saac.com/forum/gallery/178-200320120559-45222146.jpeg)

My 302 doesn't look like that? I like all the striped hoses but I must have screwed up?

No, they slipped in a GT-500 photo.   ::)

Geez, a guy makes a mistake and he never hears the end of it. LOL
Title: Re: 68 GT350 Carburetor Plumbing
Post by: FL SAAC on March 20, 2020, 05:44:48 PM
                             ~ ¿ Big block 428 ? ~

Quote from: Chris Thauberger on March 20, 2020, 12:19:35 PM
Posted this on another thread for Milo, thought you might like to have a look.

(https://www.saac.com/forum/gallery/178-200320120559-45222146.jpeg)
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 20, 2020, 05:48:47 PM
Charles,

Thank you for the photos.  These are very helpful.  It looks like in these photos there is the aluminum cobra intake so that answers my question about the cast iron thermostat housing with the vacuum tree fitting used on the aluminum intake. 

I have another question.  I see on Pete's website that with the cast iron intake there is a 1" spacer under the carburetor.  With the aluminum intake is there a spacer used with the Holley?  I can not tell by the pictures.

One more point of clarification.  From what I think I see in Pete's and Charles' pictures there is the yellow striped hose feeds the thermostat vacuum tree coming off the side of the carburetor.  Then from the thermostat tree there is a green striped hose that feeds the front of the distributor vacuum advance and a red striped hose that feeds the back of the vacuum advance.  Is this correct it is a little hard to tell for sure but certainly looks that way.

Corey
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 20, 2020, 06:06:58 PM
Yes you have the vacuum lines correct

The recall specified a phonelic spacer. It is a 1/4 inch thick. Its similar to the other spacers, but has a steel tube on the back.

The problem with the recall is everyone was doing it and there was very little consistency.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 20, 2020, 06:09:00 PM
The red striped hose has a "t"

One end connects to the vacuum advance, one to the intake and one to the tree
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Coralsnake on March 20, 2020, 06:10:55 PM
http://www.thecoralsnake.com/CobraIntakes

Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 20, 2020, 07:57:35 PM
Few more pics.

Please excuse the surface rust on the vacuum tube  ;D .  Also, the tilt column hose is not connected as I was doing some tuning and haven't put it on yet.

Title: Re: 68 GT350 Carburetor Plumbing
Post by: Corey Bowcutt on March 20, 2020, 08:06:26 PM
You guys are awesome!!!!!
Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 20, 2020, 08:22:45 PM
Quote from: Corey Bowcutt on March 20, 2020, 08:06:26 PM
You guys are awesome!!!!!

YW

If I'm lucky, I have redeemed myself to shelbydoug   ::) ::)
Title: Re: 68 GT350 Carburetor Plumbing
Post by: Special Ed on March 21, 2020, 01:02:56 AM
Holley fuel transfer tube needs fliped Charles unless its different on a gt350 than a big block the tube is bent different on the one end for clearance for pcv system. Look at coralsnake #5 post photo.
Title: Re: 68 GT350 Carburetor Plumbing
Post by: CharlesTurner on March 21, 2020, 03:41:49 PM
Quote from: Special Ed on March 21, 2020, 01:02:56 AM
Holley fuel transfer tube needs fliped Charles unless its different on a gt350 than a big block the tube is bent different on the one end for clearance for pcv system. Look at coralsnake #5 post photo.

Thanks Ed.  I just sent the carb to Drew P to fix all the leak issues it has.  Will mention the tube.