68 Fury 318 2bbl carb replacement

Zaggart

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The time has come to replace my Carter 2bbl 4608S as it won't hold a tune after a rebuild and is failing a vacuum test according to my trusted mechanic. Is the general idea that you can swap any 2bbl with another 2bbl? (Identical bases, etc.?) If anyone can weigh in here I don't have the knowledge yet to tinker with it myself. It's either try to go with a known brand or buy 3-4 Amazon generics and hope I get lucky. :)

This is the one I'm looking at as it seems pretty simple. And an aluminum spacer since the paint around the base of the old carb is a bit melty and discolored from heat.

 
FWIW, Uncle Tony claims the generic BBD he got worked better than expected.

Your current carb (the smaller BBD for 318s) has something like 1.44" throttle bores. The larger 383-size BBD has 1.56" throttle bores. The Holley you ref has 1.69" throttle bores.

Both the 1.56" BBD and the Holley, for certain, will not be direct bolt-ons for sure, due to the different size bolt patterns. There probably is an adapter to put the Holley on your small intake manifold carb mounting plate, BUT that does not mean it will run a lot better at higher rpm as the engine is still breathing through those two 1.44" holes in the intake manifold.

Find a 1979 and prior model year 360 intake so the larger 1.56" carb can be used or just go ahead and do a 4bbl upgrade with a 500cfm AVS2 or similar. The 1980 360 2bbl uses a BBD the same size as your 318 currently has. You'll also need a different air cleaner, too.

The YouTube channel "318willrun" has a short video on how to convert a factory cast iron spreadbore/TQuad intake to be able to use a non-spreadbore carb on it. As they have the same mounting stud pattern, just enlarging the primary side of the mounting flange is all that's needed.

Just some thoughts,
CBODY67
 
The time has come to replace my Carter 2bbl 4608S as it won't hold a tune after a rebuild and is failing a vacuum test according to my trusted mechanic. Is the general idea that you can swap any 2bbl with another 2bbl? (Identical bases, etc.?) If anyone can weigh in here I don't have the knowledge yet to tinker with it myself. It's either try to go with a known brand or buy 3-4 Amazon generics and hope I get lucky. :)

This is the one I'm looking at as it seems pretty simple. And an aluminum spacer since the paint around the base of the old carb is a bit melty and discolored from heat.

Just for fun I looked up your application on Rockauto. By golly they have some rebuits available. You might get lucky and get a good one. There are people tht restore carbs. (more than just cleaning and a new kit) Yours probably needs shaft bushings which are causing a vacuum leak.

 
The time has come to replace my Carter 2bbl 4608S as it won't hold a tune after a rebuild and is failing a vacuum test according to my trusted mechanic. Is the general idea that you can swap any 2bbl with another 2bbl? (Identical bases, etc.?) If anyone can weigh in here I don't have the knowledge yet to tinker with it myself. It's either try to go with a known brand or buy 3-4 Amazon generics and hope I get lucky. :)

You don't say if you want to increase the CFM to get more power at higher RPM's, or if you just want a working replacement (bolt-on replacement) for your Carter BBD that will give better idle and street drivability, correct air/fuel mixture, etc.

If it's a bolt-on replacement, look at one of my recent posts here:


It's a cheap carb, it might be worth it for you (or your mechanic) to try. I got mine from Amazon about a year ago.
 
Awesome info all, thanks. Not looking for any performance increase necessarily, beyond eliminating the rough idle we narrowed down to the carb in hot weather. I'll check out the Stromberg and Autolite mentioned in your thread too. Had no idea on throttle bores either so that's good to know.
 
These work ok. The ones I've gotten run a little rich after idle on the 318 motors. I haven't had any problems with them. I use the stove chokes. You can get it with or without ported advance for your distributor. You will need to get this gasket, because the gasket that come with them is a thin paper gasket.
About $70 on eBay.

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These work ok. The ones I've gotten run a little rich after idle on the 318 motors. I haven't had any problems with them. I use the stove chokes. You can get it with or without ported advance for your distributor. You will need to get this gasket, because the gasket that come with them is a thin paper gasket.
About $70 on eBay.

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You haven’t provided a link or product information for the pictures you posted. Can you share?
 
Here's an Amazon link for an early clone version of the Carter BBD ($88 USD):


Here's a link for the next version of the Carter BBD - with "top hat" for fuel bowl vapor recovery. I think this might have also been used on the "Super 6" slant-6 (price for this one $77):


The "brand" or manufacturer P/N for these carbs are all made up by the vendors selling them. When I bought the latter carb a year ago I knew it as a "Dromedary" brand carb.

There are over 2000 reviews for those 2 carbs when you look at all the various Amazon vendors selling them, average rating is more than 4 out of 5. Some of the reviews date to 2019.

Another carb that is being cloned in China is the 4BBL Rochester Carburetor 17085433. I'm seeing prices on Amazon of well over $600 USD for that. Here is an AliExpress link for it - price is $365:


The 2 issues I've found for the Carter BBD clone is (1) you need to buy the thicker gasket separately (they are available, should be $10 or less) and (2) the stove choke rod is not long enough to reach the connection to the carb - I'm going to weld or solder an additional length of rod to mine because I don't see a way to replace the rod (can't disconnect it from the thermostat coil).
 
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Perfect, "thundermingo" (I love these Chinese company names) it is then, thanks!

Do you guys run spacers on these also or should a properly working simple 2bbl not make additional heat problems?
 
Note that some of these gaskets have notches or passages and some don't, depending on how the throttle plate is machined, I presume the thin gaskets that come with these carbs are correct. I like the thicker gasket because I think it seals better, and yes there's the heat thing also.

Edit: Wow this is sort of concerning. RockAuto shows no Carter 2-bbl (or 4-bbl) intake mount gaskets in stock. I'm looking at 1967 but that shouldn't matter?

Some talk about this here (Mr onetwo)


But I'm curious about the carb in that thread. What is it?
 
Here's an Amazon link for an early clone version of the Carter BBD ($88 USD):


Here's a link for the next version of the Carter BBD - with "top hat" for fuel bowl vapor recovery. I think this might have also been used on the "Super 6" slant-6 (price for this one $77):


The "brand" or manufacturer P/N for these carbs are all made up by the vendors selling them. When I bought the latter carb a year ago I knew it as a "Dromedary" brand carb.

There are over 2000 reviews for those 2 carbs when you look at all the various Amazon vendors selling them, average rating is more than 4 out of 5. Some of the reviews date to 2019.

Another carb that is being cloned in China is the 4BBL Rochester Carburetor 17085433. I'm seeing prices on Amazon of well over $600 USD for that. Here is an AliExpress link for it - price is $365:


The 2 issues I've found for the Carter BBD clone is (1) you need to buy the thicker gasket separately (they are available, should be $10 or less) and (2) the stove choke rod is not long enough to reach the connection to the carb - I'm going to weld or solder an additional length of rod to mine because I don't see a way to replace the rod (can't disconnect it from the thermostat coil).

I bend the choke hole tab on the hightop carb over/down 180%.
 
You haven’t provided a link or product information for the pictures you posted. Can you share?

 
Some of the carbs (high top) have vent tubes so you can vent the carb wherever you want to, as into a charcoal return tank. I use a low pressure (appears to be .01 psi) check valve in the vent hose. From the pet store.
Some of the carbs (low top) have metal vent flaps. The vent flap job allows the carb to evaporate its gas load faster, which require more cold start cranking to fill the carb bowl.
 
The high-top carbs (aka "solid fuel" ?) have a linkage under that top-hat that operates the power piston, unlike the older type BBD that uses vacuum to pull it down.
 
While we're in the neighborhood:

On a small block it is important to verify that hte exhaust crossover passage in the heads/intake is open and flowing.
It's important on any stock carb'd engine for good cold-warmup and fuel atomization.
I've never had a bigblock get plugged up, but every 318 I've had has done it, and one did it twice, some years later.

This passage runs from behind an exhaust valve in the each head, and across thru the intake manifold, just under the carb.
When one of the 2 exh valves opens, it 'squirts' a pulse of exh gas across to the other cylinder head.
Over time the passage can get blocked with carbon. In my experience, it usually happens at the mating surface of intake and cyl head.
Chip it out with a screwdriver and suck it up as you go with the shop vac.
I had one 318 get plugged further down near the valve - that's not a fun repair to contemplate.

When the engine has been running, after a few minutes feel the intake near the carb. It should be hot to touch.
If it's not, you should fix that before bothering to put a carb on.

On a stock 318, don't bother with any carb other than an OEM-type. Not worth the fuss to try to install somethign else.
 
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