Go back and read Crazy Steve's post (post #15). In addition to the probability of worn throttle shafts/throttle body, these early Holley's typically have other problems. You can see from the picture that the bowls are warped. So you can straighten them with heat and pressure, or you can look for new, or you can put up with an external leak. Additionally, these used spun clusters, which tend to loosen over time, which will create an internal vacuum leak, and while the carb may still function, it won't function correctly if this issue is not addressed. Whether you rebuild it yourself, send it to a professional, or replace it is your decision; based on your knowledge of the issues with this particular carburetor, the tools you have available to you, your abilities, and really, how you want to proceed. I mentioned possible issues, so will also mention benefits. Once properly rebuilt, the calibration should be close enough to run as is; plus the carburetor has now, and will continue to have value over anything new to a collector. Jon.
If you choose not to use it. I would follow the advice for a Summit 500. Every guy who has bought one I have read about especially on the YBlocksforever page were no only impressed by its ease of installation but performance as well. The seem to be perfect for a Y. Ted Eaton just had an article on a slightly warmed up 272 that made 280 HP with one. If I was not running dual quads on my 292 it is what I would use. Good luck.
I bought one of those Summit carbs, and it's a well-made piece. Basically a copy of the Autolite 4100 carb that Ford used to replace the Holley in production OEM use, but re-engineered to use common Holley small parts like jets, floats and what have you. One big plus is annular discharge boosters, a extra-cost option on Holley. And Carbking brought up another common issue with used Holleys; some ham-fisted owner who overtightens the float bowl screws and warps the bowls. If they really get carried away it also warps the carb body and you now own a door stop... there's a torque spec for those, it's important that it's followed. Ford did continue to sell Holley carbs, but usually as 'service replacement' for any not-current-production Autolites. You'll generally find either 450CFM or 600s, the 450 is a great street carb on a 300" or less motor. These are 'generic' 1850s with Ford-spec jetting for the application, so you may need to re-jet. These will have a Ford part # stamped under the Holley stuff.
i agree, rebuild it yourself. If the throttle shafts feel good I would have no problem putting a kit to it. as far as tools its not like you need a mill, lathe or even a band saw. its all basic hand tools. If you can't figure out how to rebuild that carb or the tools to do it you will never be able to swap the intakes etc over by yourself either.
I came close to using a spread-bore intake on my car since I had a good Holley SB that needed to be freshened up. But opted for a Holley 700 CFM, brand new from Summit with the square pattern. No dicking around and it worked perfectly out of the box with the usual tuning.
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