Carter AFB 4-barrel carburetors

[carbking]

We are getting more and more questions concerning the Carter type AFB carburetor by phone, and there also seem to be several on these forums.

 

The genuine Carter AFB has always been one of my favorite carburetors, and (opinion) the very best 4-barrel for street use until the 4th year of production of the Rochester Q-Jet. Still today, in my top three 4-barrels for street use.

 

Here are a couple of links that AFB rebuilders might find useful:

 

http://www.thecarburetorshop.com/AFBtuningtips.htm

 

And

 

http://www.thecarburetorshop.com/Idlemixturescrews.htm

 

Jon

[padgett]

I like the AFB also (particularly the three barrel) but were available in A Lot of sizes, mostly from a 450 to a 750. For dual quads onna SBC I liked a 450 rear and a 500 front with progressive linkage (made one from a spoon oncet) so most of the time it ran on the rear primaries. Always adjusted for a small flow through the front primaries to keep the fuel from going stale. Nice thing about both the AFB and the Q-Jet was the air valve secondary that kept the air flow down to the demand. Problem was the adjustable spring tension on the secondaries, first thing a wannabe did was to richen the primaries and back off the spring. This caused two things: a massive lean bog off the line as the secondaries flopped open and  with a Q-Jet on a big block would often empty the float bowl and bog again at the top of third.

 

As to too big a carb on too small an engine I used to have a Corvair Corsa autocross car with a late 750 CFM (800 wasn't needed) Q-Jet on a 4 runner spider for the 164 cid flat six. Once you tuned the primaries lean and the spring just tight enough to control the air flow it was both very responsive and won a lot of autocrosses.

 

Also with the dual AFBs on my Sunbird in later years, could get 22 mpg and very smooth running (did have the jets leaned way down, aftermarket carbs were jetted way rich. Did help to have the Carter "Strip Kit" with a nice assortment of jets and rods.

 

ps Jon is the real professional, I an just an amateur but listened a lot to what Doug Roe said.

Edited December 6, 2016 by padgett (see edit history)

[60FlatTop]

I remember learning on the AFB's with my first exposure to 4 barrel carbs. Then the WCFB's. The Q-Jets got popular while I was in the Navy. They were a little fussy for me in my early 20's. I was 22 years old when I had a '68 Riviera with one on it. Holley came out with a spreadbore that I used on my 430 Riviera, but it was too much carb. I live near Rochester and a friend was in QC, he showed me the tricks and I have been OK with them since. The 4GC's aren't bad either. I like the AFB's best. My '64 is running one with pieces of the original, a '58 Lincoln AFB, and a '59 Caddy AFB, all kind of put in a pile and the best assembled into one.

About 20 years ago i had a '56 Olds with a 4GC that was being a real PIA. I was lucky enough to take it to Tom Toal and work with him for a few hours on it, although both of us together couldn't get it right. Tom was a Rochester Products carburetor engineer who joined the company in the early stages of the Q-Jet design. He told me he took credit for the long screws in the back barrels. He said short ones would fall into the manifold. I had to bring an overhaul kit and he charged me $75 for his time. What a great bunch of stories he had to tell about GM.

He recognized we were both working at a similar skill level and he was getting old with some noticeable Parkinson's. At one particular frustrating point he looked at me shaking a little and asked "Did someone send you here to set me up?" It was that hard and I took it as a compliment.

Carbs are all kind of fun if you approach them right. Tom said carburettion was an art form. Fuel injection is engineering. Explain that in 25 words or less and you got it.

Bernie

[Guest Grumpy's Auto Shop]

I gotta say, I'm not a fan.

And this isn't because I voted for Reagan.  It's probably due to some silly prejudice.

 

Over the years I have had countless cars/trucks with AFBs which worked just fine, but I didn't like the way they 'looked'.  There is probably a lesson in bigotry somewhere in this.

The last AFB I had was on a '79 F250 4x4 with a 400M which could pull down surplus farm buildings and haul them away without losing ANY fuel economy. I always wanted to put an Edelbrock on that truck but why spend 6 hundo on a $250?

 

[padgett]

Best things about an AFB is that it is smaller than a double pumper Holly (for dual quads had to mount sideways which made for strange linkages. AFB fits inline) and it has larger float bowls than a Q-Jet (no sudden bog near the end of a 1/4).

 

Of course I learned on 2" SUs (triple HD8s) & still have a Uni-Syn so like lotsa carbs. That said since 1970 have been able to get More Power from a FI so prefer those.

 

That said still have a few tripowers with 2Gs and dual quad manifolds with AFBs stuffed in odd corners. Am tempted to put a set on the Judge.

 

" spend 6 hundo on a $250" some of the most interesting things have happened because X was sitting in one side of the garage, Y was in the other, and it was raining. Often a few longnecks made anything possible. Back in the day $$$ was rarely involved.

Edited December 7, 2016 by padgett (see edit history)

[60FlatTop]

Bigotry on a Carter carburetor? You should have talked about '50's Holley's with my group.

B

[padgett]

Never saw a Holley I could not make leak.

[carbking]

13 hours ago, padgett said:

Never saw a Holley I could not make leak.

Padgett - made one into a lamp once, so it didn't leak fuel; HOWEVER, little electrons used to run down the side of the lamp, run off the end of the table, and bounce on the floor!

 

Jon.

[Guest Grumpy's Auto Shop]

I guess we should be thankful that Lucas never made carbys...

[Willie Wurke]

Has anyone had any experience with a Fish carburetor? ( that was the brand name !  )

I happen to have one!  Really odd construction.

[countrytravler]

No! I'm not doing what you think when you 1st see this picture! LOL This is me in the center working on the front carb. Taken in 1980 at the dragstrip in Racine WI at the Union Grove Dragway.

The car is a 1962 Impala SS 409-409 4 speed. 2 Carter AFBs.

The front carb had float issues. They are simple for sure.

We enjoy your knowledge of carbs and thank you for sharing your knowledge with us.

I got really good on rebuilding and hot rodding the old Rochester F.I. that were found on the Chevy and Pontiacs.

Dave

[countrytravler]

1 hour ago, Willie Wurke said:

Has anyone had any experience with a Fish carburetor? ( that was the brand name !  )

I happen to have one!  Really odd construction.

 

 

[carbking]

1 hour ago, Willie Wurke said:

Has anyone had any experience with a Fish carburetor? ( that was the brand name !  )

I happen to have one!  Really odd construction.

 

This item best discussed with the Easter bunny, the tooth fairy, and the pot of gold at the end of the rainbow!

 

Yes, it exists. Yes, it is called a carburetor, although I do not know why.

 

Jon.

[padgett]

Rochester FIs (particularly the late large plenium) won a lot of SCCA B/P races for me particularly when fitted with reject (too high flow) nozzles from Detroit Diesel Allison and some hogging out courtesy of the Swartz Creek parts house. Go one to 900 cfm by opening up the choke tube. Ran mine with a Delcotronic ignition that required a 1111064 distributer.

 

Also found that TCS switches were great for curing a leaking coasting signaling valve.

 

Still have a few things lying around. These used to make decent speaker stands.

[countrytravler]

Ran 11.20s in 65 with my uncles 62 Fuel that he bought new and still owns it today.

[Willie Wurke]

On ‎12‎/‎8‎/‎2016 at 6:06 PM, carbking said:

 

This item best discussed with the Easter bunny, the tooth fairy, and the pot of gold at the end of the rainbow!

 

Yes, it exists. Yes, it is called a carburetor, although I do not know why.

 

Jon.

  Jon;  I think it comes closer to being throttle body fuel injection.( Fuel nozzle and a throttle valve ! )

  Thanks for the comments on this post. I expected as such when posted it.

       as ever, Willie W.

[carbking]

Willie - the grouping is because when discussing the Fish, you have two groups of enthusiasts: (1) the "true believers", and (2) everyone else.

 

My mentor in the carburetor business actually ran a back to back 1000 mile test of a Fish vs a 1904 Holley on a 6-cylinder Ford. The 1904 won the test; the Fish finished the test and actually did produce somewhat better fuel economy than the Holley, but that is ALL the good that could be said about it (and there was LOTS of BAD).

 

There are literally millions of pixels that have been disturbed on the internet trying to turn the Fish, the Pogue, and other high mileage fairy tales into carburetors. So far, no carburetor has been able to flout the laws of non-nuclear physics.

 

The very best I can say about the Fish, is that it is an excellent conversation piece (as long as it is on the mantle over the fireplace, not on an engine).

 

Jon.

[Guest Grumpy's Auto Shop]

The true irony is that fish ARE carburetors that work backward.

[padgett]

Yes, drive one long enough and the gas tank overflows.

[countrytravler]

Have you seen one of these?

Edited December 10, 2016 by countrytravler (see edit history)

[lump]

34 minutes ago, countrytravler said:

Taken in 1963. Friend of my dad.

Wow. AWESOME photos, Country!!! I would have guessed that those color photos were of a recently restored 409 Chevy, since the engine compartment seemed almost "too nice" for a production-line produced car. It's nice to know that this photo was taken in 1963. 

[countrytravler]

6 minutes ago, lump said:

Wow. AWESOME photos, Country!!! I would have guessed that those color photos were of a recently restored 409 Chevy, since the engine compartment seemed almost "too nice" for a production-line produced car. It's nice to know that this photo was taken in 1963. 

 

 

The black and white were taken at the GM tech center in Warren MI in 63 where my dad worked. The color is a recent picture of the car just restored with the modified FI unit.

 

Edited December 10, 2016 by countrytravler (see edit history)

[lump]

WOW, Country. Now you've REALLY got my attention. Do I understand you to mean that the color photos of the 409 with 2 AFB's is actually a modified Fuel Injection system???

 

At a SEMA show a few years back, I saw some new Fuel Injection units which had been produced to look exactly like the old Stromberg 97 carburetors. But I have never before heard of anyone doing that with FI units which look like factory muscle car carburetors. If so, that would be cool news indeed! 

 

Thanks for the photos, by the way. I really like this forum. 

[countrytravler]

MAN! I really got you confused. Let's see if I can make sense out of this.

This is the car with the 409 FI. 2 prototypes were built in 62. This car was just restored with this 409 FI installed. These engines were just on the dyno that I have been told. My dad is gone so a lot of the info went with him.

[countrytravler]

These are the pictures taken from a 63 409 mag that my dad worked with at the GM Tech Center in Warren MI on the Cater AFBs.

[countrytravler]

I also enjoy your articles on the carb because that was my weak point in my racing career with the 409s.

Here is my last car that I built, 1963 Chevy that I took 2nd in the Nationals in 1987. This was a 409 on a Holly 2 barrel that ran the 12.70 bracket.

 

Edited December 10, 2016 by countrytravler (see edit history)

[countrytravler]

This is just a regular 409 car that was recently restored. I was showing this because this thread was about the Carter AFBs.

[countrytravler]

 

[countrytravler]

Its chain driven. What you see up top is a fuel distributor. This was made to be an option but project was scrapped and this is the only unit left. There are more info on 348-409.com

 

 

[countrytravler]

4629576004 E-bay number Tom. In case you can't get that till later- Heres what i believe to be the only Fuel Injected Chevrolet 409 set up like this known anywhere i picked this up from a fellow who owned a trucking company back in the early 60s I have had this for 25 years the fellow i got this from told me a testing lab in Ann Arbor Michigan which is 40 miles from Detriot sent workers in white lab coats out to his garage and installed 3 of these setups on 409 truck engines and whenever they had problems the guys in the white lab coats would show up and repair them and he said they ran real good and made a strange hissing whine when they were running and really made the gravel trucks haul when the testing was done the lab came out to remove them but one setup was missing and from what he told me they were real pissed but what had happened is he removed one and took a back hoe and buried one of them all wrapped up to protect it in his back 40 and left it there for a year until the heat was off and I kept it out of sight for the last 25 years and for the first time since 1964 here it is so this is the story I was told about it and nothing made up.Take a look at the pictures its kind of like a diesel except lower fuel PSI and has a chain driven injection pump that's oiled by lines from the engines oil pressure but are not connected in the picture the pump has line to each port and shoots fuel with the engines firing order and has a simple 4 barrel throttle body to control the air I have the original fuel pump but I would use some of the today's fuel pumps and vacuum operated fuel pressure regulators with this setup there a lot better and I think you would end up a real neat one of a kind engine that would stop em dead in their tracks at any car show anywhere.I really don't want to sell it but its been sitting around doing nothing in my barn so if the price is right you could be the proud owner of what I believe is a one on a kind piece and don't ask me what brand it is there's no name or ID tag on it but the intake is the low horsepower GM intake and would fit on a 348 also.What you will get in this auction is the intake with pump,throttle body.lines,front cover,cam sprocket everything is here you will need to set it up I even have an extra injection pump.What you don't get is my friends engine we set it up on or the valve covers we just dressed it up so you could see what it could look like under the hood so if you're a serious 409 collector here's your chance to own what I believe may be the only fuel injected 409ci Chevrolet motor like it in the world trust me I have talked with some top notch 409 people they have never seen anything like it and you can bet once you get this running and in a car I am sure some well known Hot Rod magazines will be more than willing to get your car on the front cover.

It's a belt driven thing off the front of the block, set up like an a/c compressor would be, on the passenger side. Has tubing running to an intake.

Don

[countrytravler]

 

[countrytravler]

http://www.jalopyjournal.com/forum/threads/factory-fuel-injected-409.672207/

[capngrog]

Countrytravler,

 

Thanks for the information on the Chev 409 fuel injection system.  I've never even heard of this system.   It's amazing what could be done mechanically prior to the computer age.

 

As to the Carter AFB, I've never been a fan.  In the early 1970s, I built up a 1964 Corvette coupe for time trialing.  We ran everything from large parking lots to abandoned roads to real racetracks (PBIR, Sebring, Road Atlanta etc.).  I initially had an AFB on the engine (1970 350 C.I., L.T.-1), but it would consistently flat spot under hard cornering.  It could have been that I was not tuning the AFB properly, but all the hot dogs ran Holleys, so that is what I went to: a 780 cfm single pumper.  It worked great and could be tuned to handle just about any track condition you might encounter.  The Holley was a bit intimidating at first, with all the variable bits and pieces, but, once I got into it, I felt quite at home with it.  I'm now assembling (from old parts I had laying around) a 750 cfm Holley for a RatRod project).

 

I currently have a mildly modified SBC Chevy 350 which is running an Edelbrock "Performer" carburetor.  I understand that this carburetor is almost the same as the old Carter AFB.  I'm quite satisfied with the Edelbrock carburetor, but I'm just running it on the street with no hard cornering.  I find it interesting that the old Carter AFB now has an Edelbrock label on it, but is actually made by Weber.  Who'd a thunk it?

 

Cheers,

Grog

[countrytravler]

I have been into the W engine since it came out in 58. I was 6 and my dad would bring these cars home from the GM Tech center. We had Zoro wrenching on cars in our driveway testing and street racing the cars on Woodward Ave. So, I had a cool street racing with dad childhood. I have never seen a 09 FI but heard about it. GM had things going on in Ann Arbor MI because

 of testing labs.

Edited December 10, 2016 by countrytravler (see edit history)

[capngrog]

20 minutes ago, countrytravler said:

I have been into the W engine since it came out in 58.

 

Didn't the Chevrolet "W" engine first appear in trucks around 1956 or 57?  I seem to recall that they were out for a couple of years before being installed in the 1958 Chevys.  My first car was a 1958 Chevrolet convertible with the factory tri-power, 3-spd manual transmission with floor shift and a 4.11 positraction rear end.  I loved it, but alas (did I really say "alas"?) my first permanent duty station in the Air Force was Great Falls, Montana ... definitely not convertible country.

 

Cheers,

Grog

[countrytravler]

Oct of 1957

http://www.348-409.com/general.html

[carbking]

1 hour ago, capngrog said:

Countrytravler,

 

 

 

I currently have a mildly modified SBC Chevy 350 which is running an Edelbrock "Performer" carburetor.  I understand that this carburetor is almost the same as the old Carter AFB. 

 

Cheers,

Grog

 

With all due respect, this is like saying a Yugo is almost the same as a Ferrari! After all, both have 4 wheels!

 

Your hard corning issue of yesteryear could have been alleviated by using bowl baffles. Which would have then allowed sufficiently hard cornering to bring up a second issue....fuel slosh from the bowl vents. That issue was corrected by using overhead vents similar to those used on the old dual quad WCFB's. And while it is quite possible to make the AFB's (at least the genuine versions) corner exceptionally well, it is certainly easier with the Holleys.

 

Jon.

[padgett]

I always used front carbs with idle circuits to keep from getting stale gas in the bowls. That FI is strange, not at all like a Rochester which had a fuel pump driven by the distributer and this has no plenium to speak of. Looks more like something that has a blower like a Paxton & needed to pressurize the carb.

 

ps  AFAIK Edelbrock bought Carter.

 

pps and Carter supplied many Q-Js (ones that say "Carter" on the side) which begat the 1,000 cfm thermo-quad.

Edited December 11, 2016 by padgett (see edit history)

[capngrog]

7 minutes ago, carbking said:

 

With all due respect, this is like saying a Yugo is almost the same as a Ferrari! After all, both have 4 wheels!

 

Jon,

 

How do you really feel about the Edelbrock carburetor?  Seriously, though, I don't know the functional difference between the real AFBs and the Edelbrock.  Is it primarily a difference in quality, design or both?  Considering your Yugo/Ferrari comparison, I suspect it is both.  I would value your opinion on this.

 

Cheers,

Grog

[countrytravler]

It's like a throttle body without the injectors. If you look close, fuel lines are routed like the multi-port injection. The pump is timed by the cam gear. This is a B&W unit. Rochester had nothing to do with it. And on a dual quad 409 with front carb idle circuit, you would get cylinder wash. That was with 60s tech, not so today. With my 392 Hemi with blower, fast fuel is the only way to go.