Quote:
Originally Posted by rsk289
OK, this a real can of worms -
I'd like to use a 4100 on my 5-bolt hipo, as close to correct as I can get within reason. I'm thinking of using a C3OE-AJ, 1.12. Most of those I can find have auto chokes. I'm pretty sure an original '64 street car would not have had any kind of choke - correct? Can an auto-choke carb be converted? Anything in particular I should be looking for (apart from a miracle)?
Roger
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I will assume that you are interested in HP289 powered Cobras. Instead of recreating an outline I cut and pasted a section from my engine notes. C3OF-AB models are extremely rare. I have only held one in my hands. They were not used in production long. C3OF-AJ models, 1963 or 1964 versions, are not as rare as you might think in the used parts market. The only cars they were stock for were Cobras, Fairlanes, and a few Comets. Most Cobras lost their original carburetors long ago, small number of Fairlanes have them now, and there cannot be many Comets using them still as not many were made to begin with. The C4OF-AL model dated for a Cobra is pretty rare. I have been hunting one since 2004 and not found one anywhere but on the Cobra it left SAI in. The toughest ones to locate are carburetors with assembly tag dates appropriate for engines assembled circa June, July, and August 1964. Otherwise many cars were sold new or had offered as dealer accessory a C4OF-AL carburetor. If a dated assembly tag is of no interest just finding a decent carburetor is still tough and then you have to overcome the competition for them. People hunting them include owners of Fairlanes, Mustangs, Cobras, Comets, Tigers, or any other Ford for which it was offered as a dealer upgrade for. The C4OF-AT is the rarest O.E. HP289 Cobra carburetor that I know of. It was specific to 1965 model year HP289 and C4 automatic transmission Fairlanes and a few new 1965 Cobras. I only know where two are, both on the car they left a factory on and one is a friend’s Cobra.
Your best bet for obtaining a genuine HP289 specific model is a C3OF-AJ. The problem that I have had here is only the one removed from a Cobra decades ago and stored well came to me 100% complete. All the others I have purchased or helped other Cobra owners with were purchased missing a significant number of small parts. Ford did like most companies then and now so there were time frame specific changes to small parts. I have purchased a C3OF-AJ model and then one or two Galaxie versions of the same time period to harvest small parts from to create one complete carburetor. The worst part to go hunting for is not the booster clusters calibrated for high performance applications but the small brass plug used to seal the spark vacuum port that does not get used with HP289 engines. The part is actually a Holley part made for Ford application carburetors. The earliest use I have found has been 1963 Galaxies with 427 8V engine carburetors doing the same job. The brass plugs are rather soft and usually get damaged a little to severely by people removing them with screw drivers in poor condition or too small for the task. The fragile brass plugs were not used for long by Ford on the 427s (and later Shelby Mustang carburetors). They were superseded by plated steel screws (which are fairly rare themselves in undamaged condition) for Ford performance applications through the 1967 model year. The 1963 design plug has tapered pipe threads. The brass plug used in C4OF-AL models has a straight thread design. The two designs will not interchange.