News:

SPECIAL NOTICE - See SAAC-50 Forum for DATE CHANGE for SAAC-50

Main Menu

Replacement carbs

Started by charlie D, March 21, 2019, 03:20:04 PM

Previous topic - Next topic

1967 eight barrel

I am running the re-issue obtained via Carl's Ford Parts. He supplies everyone else as he contracts with Holley to manufacture them. They are better in many ways than the older version. If you have them rebuilt make sure the builder is well known and the throttle shaft bores are re-bushed.

                                                                                 -Keith

charlie D

I finished the carb switch, so here's what I ended up doing.  I bought a pair of Holley 4160 600 CFM carbs, one with an electric choke and one without. These are aluminum single fuel inlets with vacuum secondaries so they mimic the originals in function and are slightly lower CFM. I took the advice for the 1/4" phenolic spacer and related hardware to minimize the vapor lock issue. The new carbs come with a fuel fitting that sits sideways along side the fuel bowl, so that needed to be replaced with a straight out the side fitting in order to use my current fuel lines. The rear, manual choke, carb has a large vacuum port that points forward between the two carbs. That port is in the way of the throttle linkage, so it was removed, tapped, and plugged with 1/8 NPT plug. The base of the carb is also shaped forward where that vacuum port is and that forward shape is in the way of the flat mounting bracket for the throttle linkage. So the bracket had to be modified for clearance. I cut the bracket to mount on each side of the carb with no center section. It is still solid, but the alignment is critical to prevent binding. The next fiddly piece is the new carbs float adjustment screws are round and tall, so they interfere with the air cleaner base. I tried a 1/2" spacer, but it was too tall for the hood to close--touched. I made a spacer about 1/4" thick from some neoprene rubber and that allowed good clearance. Start up was uneventful, ran smoother than I can remember. The idle was much too high and it took a little fiddling between the idle adjustments on the carbs and the linkage to get that right.
I am now ready for a road test when the weather turns dry and will know how the vacuum secondaries work under load and if they need any adjustment. Overall, I am pleased with what I have right now. Wonderful not to have any leaky carbs! I figure I will send the original carbs out for a rebuild while that can still be accomplished and store them for someone who wants to go to a fully original setup. Thanks again to all of you who gave me part numbers and suggestions on this project, they were invaluable. Couple of photos attached.
Charlie D

shelbydoug

You should apply for a Doctorate of Carburetor Technology. The only issue is, there are few that know or understand what you are talking about?

I do. You have my vote. Nice going...except all of that polished aluminum. I need special glasses to see it?

I stayed with the green/gold/crud original finish. It matches my Keds sneakers and cuffed Chinos better.  ;D
68 GT350 Lives Matter!

pbf777

#18
      I would go ahead and remove the mechanical choke components as they apparently serve no useful purpose; if not be sure to mechanically lock the plate in the open position, often just a section of stiff wire engaging the cable retention bracket to the choke lever arm will suffice.  That is if you didn't already, as the photo does not clearly depict such, at least for my eyes anyway.

     Scott.

Bob Gaines

Quote from: charlie D on June 10, 2019, 09:34:02 AM
I finished the carb switch, so here's what I ended up doing.  I bought a pair of Holley 4160 600 CFM carbs, one with an electric choke and one without. These are aluminum single fuel inlets with vacuum secondaries so they mimic the originals in function and are slightly lower CFM. I took the advice for the 1/4" phenolic spacer and related hardware to minimize the vapor lock issue. The new carbs come with a fuel fitting that sits sideways along side the fuel bowl, so that needed to be replaced with a straight out the side fitting in order to use my current fuel lines. The rear, manual choke, carb has a large vacuum port that points forward between the two carbs. That port is in the way of the throttle linkage, so it was removed, tapped, and plugged with 1/8 NPT plug. The base of the carb is also shaped forward where that vacuum port is and that forward shape is in the way of the flat mounting bracket for the throttle linkage. So the bracket had to be modified for clearance. I cut the bracket to mount on each side of the carb with no center section. It is still solid, but the alignment is critical to prevent binding. The next fiddly piece is the new carbs float adjustment screws are round and tall, so they interfere with the air cleaner base. I tried a 1/2" spacer, but it was too tall for the hood to close--touched. I made a spacer about 1/4" thick from some neoprene rubber and that allowed good clearance. Start up was uneventful, ran smoother than I can remember. The idle was much too high and it took a little fiddling between the idle adjustments on the carbs and the linkage to get that right.
I am now ready for a road test when the weather turns dry and will know how the vacuum secondaries work under load and if they need any adjustment. Overall, I am pleased with what I have right now. Wonderful not to have any leaky carbs! I figure I will send the original carbs out for a rebuild while that can still be accomplished and store them for someone who wants to go to a fully original setup. Thanks again to all of you who gave me part numbers and suggestions on this project, they were invaluable. Couple of photos attached.
Charlie D
Too bad that vacuum secondaries do not have a vacuum port so that a hose can be run from on to another which equalizes the vacuum between the two like the factory duel four carburetors. It will not be quite as smooth given the secondaries might not be opening at exactly the same time like they typically do when equalized..
Bob Gaines,Shelby Enthusiast, Shelby Collector , Shelby Concours judge SAAC,MCA,Mid America Shelby

Mike James

I also have a pair of repops I will sell for half the price of new ones.
They are bj/bk but no date codes.

pbf777

Quote from: Bob Gaines on June 10, 2019, 11:21:56 AM
/quote]Too bad that vacuum secondaries do not have a vacuum port so that a hose can be run from on to another which equalizes the vacuum between the two like the factory duel four carburetors. It will not be quite as smooth given the secondaries might not be opening at exactly the same time like they typically do when equalized..

    The "conversion" kit for this is: Holley # 20-28 consisting of two covers each with vacuum ports to aid in the synchronization.

     Scott.

JD

Does the conversion kit transform them from dueling to dual?  (Sorry Bob I couldn't resist)
'67 Shelby Headlight Bucket Grommets https://www.saacforum.com/index.php?topic=254.0
'67 Shelby Lower Grille Edge Protective Strip https://www.saacforum.com/index.php?topic=1237.0

shelbydoug

Quote from: JD on June 10, 2019, 05:47:46 PM
Does the conversion kit transform them from dueling to dual?  (Sorry Bob I couldn't resist)

;D
68 GT350 Lives Matter!

1967 eight barrel

I couldn't get the reproductions to run right no matter what was done. Holley must have went off-shore.
Drew is a noted rebuilder and one of the few that know them in and out, not to mention concours restoration and correction.
These were mine.
Look at the reason why they wouldn't then after he blueprinted them and installed them on his 427 Galaxie and tuned them.

Sadly it shows the current quality. Even some of the air bleeds were two different sizes.

http://fepower.net/simplemachinesforum/index.php?topic=7534.0