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Discussion Starter #1
I've recently come into possession of a C6AF, 1.08 venturi, Autolite 4100 and would like to install it on my C code 66 (stock 289 w/ AT). Although this C6AF carb is built for an FE (390 or 428 w/ emissions & AT), and needs a rebuild anyway, can it be re-calibrated (built down ie> smaller jets etc) to C6Z* specs and be expected to operate correctly for a small block 289? I've done some searching through forum posts and have not revealed a definitive answer. Do the internal carb passages differ with EACH varying application or are they essentially the same body with varying jets, boosters etc? Do I have a "do-able" rebuild or an old paperweight? ANY input would be greatly appreciated. THX in advance.
 

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The answer is yes. Simply start with the jet sizes and the specific tuning for whatever is closest to your motor. Although each carb was tuned for specific performance, the Ford replacement carbs were just a few to cover all the ones out there. You have an advantage that it is a 1.08 venturi. You can even tune a 1.12 for operation on a small block (Ford did it with non-hipo motors, just sayin'). Mass rebuilders take apart a bunch of 'similar' carbs and rebuild them as a batch. So having the correct boosters is a rarity in one of those. Yet, they still ran. Relax. It will be OK. Look up the settings in the FSM.
 

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I am running a 1.08 carb of similar spec and LOVE it without having changed a thing. My 289 is hungry enough that it suits it just fine. The 4100 is by far the best carb I've ever had on it.
 

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I have one too. Wish I had an adapter of some sort so it would bolt onto my Performer RPM.
 

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I have one too. Wish I had an adapter of some sort so it would bolt onto my Performer RPM.
I'm sure there is something available or can be machined for you.
 

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Discussion Starter #6
The answer is yes. Simply start with the jet sizes and the specific tuning for whatever is closest to your motor. Although each carb was tuned for specific performance, the Ford replacement carbs were just a few to cover all the ones out there. You have an advantage that it is a 1.08 venturi. You can even tune a 1.12 for operation on a small block (Ford did it with non-hipo motors, just sayin'). Mass rebuilders take apart a bunch of 'similar' carbs and rebuild them as a batch. So having the correct boosters is a rarity in one of those. Yet, they still ran. Relax. It will be OK. Look up the settings in the FSM.
Thank you for the info. Good to know.
 

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I have one too. Wish I had an adapter of some sort so it would bolt onto my Performer RPM.
Easy enough to do. I have a 4100 on my RPM manifold.
Also works on the early Cobra 4-hole manifolds. That's what I originally had.

743987
 

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Actually, the answer is "somewhat". Can you get it to run decently? Sure. Can you "re-jet" it to a particular "spec"? Not unless you have the correct boosters. Jet size is only a small part of the equation. The boosters are the key. The size of the venturis, discharge ring and holes, emulsion tubes, air bleeds, channel restrictors... all those are what "calibrates" the carburetor. Unfortunately, I have never found a book that describes all the unique particulars of boosters to know which ones are dimensionally similar (the inside/outside diameters of the annual rings) and the other specifics. Very experienced 4100 "guru's" will heat up the soldering irons and get out the drill bits and "tweak" the boosters to a particular tune. It's not rocket science but it's damn close. LOL. I've played with them to some degree... heck, I ran a 1.19" off a '58 292 on a 221 small block for a while with decent results but I think I was just lucky and although I'll never know if it was the carburetor or my right foot, it never got the fuel mileage it did with it's original 2100.... :cool:
 

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Pony Carburetors used to sell a hybrid 1.08 front 1.12 rear 4100 4V with some custom tweaking. I'd like to run something like that. I am very pleased with the mpg and the giddy-up I get outta my little 289-ish engine. I'm sure I could get more giddy-up maybe at the cost of some economy by swapping the intake, having done more head work or buying Expensium heads, going with some Tri-Ys, or swapping for a cam that sounds like I have two plug wires off until WOT...but after trying 4 different carbs, I'd still be running a 4100.
 

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Pony Carburetors used to sell a hybrid 1.08 front 1.12 rear 4100 4V with some custom tweaking. I'd like to run something like that. I am very pleased with the mpg and the giddy-up I get outta my little 289-ish engine. I'm sure I could get more giddy-up maybe at the cost of some economy by swapping the intake, having done more head work or buying Expensium heads, going with some Tri-Ys, or swapping for a cam that sounds like I have two plug wires off until WOT...but after trying 4 different carbs, I'd still be running a 4100.
I have one of the Pony spread bore carbs which John called it, the front bore is 1" . Great carb. Which some one had continued his business. Years agoa someone on a truck forum placed a copper plumbing reducer in the front bores. I believe the one in mine is plastic.
 

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As Woodchuck alluded to, 4100s take a bit of calibration and the info you need isn't low-hanging fruit.
Here's a prototype for a blower application. Sure to be a real treat to calibrate.....

744048


744049
 

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Discussion Starter #12
Actually, the answer is "somewhat". Can you get it to run decently? Sure. Can you "re-jet" it to a particular "spec"? Not unless you have the correct boosters. Jet size is only a small part of the equation. The boosters are the key. The size of the venturis, discharge ring and holes, emulsion tubes, air bleeds, channel restrictors... all those are what "calibrates" the carburetor. Unfortunately, I have never found a book that describes all the unique particulars of boosters to know which ones are dimensionally similar (the inside/outside diameters of the annual rings) and the other specifics. Very experienced 4100 "guru's" will heat up the soldering irons and get out the drill bits and "tweak" the boosters to a particular tune. It's not rocket science but it's damn close. LOL. I've played with them to some degree... heck, I ran a 1.19" off a '58 292 on a 221 small block for a while with decent results but I think I was just lucky and although I'll never know if it was the carburetor or my right foot, it never got the fuel mileage it did with it's original 2100.... :cool:
Woodchuck, I'm with you on this. I've been pulling my hair out (what's left of it) trying to locate a source that describes specific characteristics of varying boosters to NO avail. I'm obviously new to the 4100 party and am just now wading through the mud which countless others before me have since negotiated long, long ago. 😵😩 Just going to lean into it and hope for the best!
 

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Call the guys at Daytona Auto Parts. Rick @ NPD turned me on to these guys after Jon passed w/ Pony Carbs. I've personally delivered several of my 4100's to them and they do awesome work. They have an extreme knowledge of all types of carbs and should be able to give you the answers you need. They're in New Smyrna Beach. The 4100 on my 64 is one of Jon's first carbs and I'm around 430,000 miles on it and it still can get around 20 mpg's. He put it on in Sept., 2000.
 

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Discussion Starter #15
Call the guys at Daytona Auto Parts. Rick @ NPD turned me on to these guys after Jon passed w/ Pony Carbs. I've personally delivered several of my 4100's to them and they do awesome work. They have an extreme knowledge of all types of carbs and should be able to give you the answers you need. They're in New Smyrna Beach. The 4100 on my 64 is one of Jon's first carbs and I'm around 430,000 miles on it and it still can get around 20 mpg's. He put it on in Sept., 2000.
THANK YOU
 

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Discussion Starter #16
Came upon an ad in my local Craigslist yesterday and lo and behold it was for a C6ZF-B. Upon inspection (owner allowed me to crack it open) I was very pleasantly surprised to see that it was virtually unmolested. Aside from the mismatched floats (primary is brass, secondary is plastic or Bakelite) the carb is jetted correctly and more surprisingly has the correct CH primary and A secondary venturi boosters. All parts are present and free moving so I bought it on the spot. Thanks to you all for taking the time to respond to my post, I was given some very useful information. You're all VERY HELPFUL. THX
 

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I have one too. Wish I had an adapter of some sort so it would bolt onto my Performer RPM.
Why won’t it work. Mounting flange too thin to the a good seal? Doesn't the carb spacer solve this? Anyone know if this also applies to the Performer 289? I have. A brand new one I was going to use with my 4100 on my 68 289.
 

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The 1/4" thick plate in post #7 should work fine. Edelbrock states that the carb mounting flange on the Performer 289 is a square flange.
It looks like the same "square flange" is used on their Performer RPM. I don't KNOW that it will but the plate should work.
 

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The 1/4" thick plate in post #7 should work fine. Edelbrock states that the carb mounting flange on the Performer 289 is a square flange.
It looks like the same "square flange" is used on their Performer RPM. I don't KNOW that it will but the plate should work.
Who sells the plate? Does adding the extra 1/4” cause hood interference issues With the already taller intake? I thought the 4100 was a square flange. The problem has been the spacer is open on the bottom and doesn’t seal. Some folks have had success using the Boss 302 style spacer.
 

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Who sells the plate? Does adding the extra 1/4” cause hood interference issues With the already taller intake? I thought the 4100 was a square flange. The problem has been the spacer is open on the bottom and doesn’t seal. Some folks have had success using the Boss 302 style spacer.
Plate is a "custom" one...... bandsaw/hacksaw, a hole saw and a drill to make that happen.
Performer 289 I doubt is taller than stock...... guaranteed the Performer RPM is though and the carb being a little more than 1/4" higher poses no issue there.
Autolite 4100's are square flange but have a narrow and "hollow" footprint because of the way the base is. That's why you have to be specific on the type of
spacer.
 
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