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By dennis22 - Last Month Hi all, Just trying to ID this carb. I purchased the B intake and this carb was included. I’d like to rebuild it and use it on my next Y build but want to see what it is and if it’s suitable. I should add, this is what I’ve come up with so far. Autolite 4100 C2SF B A2JE C=1960-1970 2= 1962 S= Thunderbird F= General parts B= A= 2= J= E = By KULTULZ - Last Month C2SF-B = EXACT APPLICATION A = DESIGN CHANGE F = FUEL - GENERAL F4100 1.12 FLOW RATINGS - By Ted - Last Month My information matches yours. C2SF B according to my material is from a 1962 Thunderbird with the 390 engine.  It was not apparent in the pictures but there should be “1.12” cast within a circle on the left side primary fuel bowl.  At the front & lower left of the carb base should also be a stamped number corresponding to the part number on the tag. The above chart posted by Kultulz on the cfm ratings corresponds to what I have for the cfm ratings for those particular carbs.  The 1.12” venturi Ford carburetors generally flow in the neighborhood of 520 cfm while the 1.08” venturi carbs flow around 440 cfm.  As a general rule, the 1.12” carbs work well on the Ford Y engines.  Being a vacuum secondary carburetor, the secondaries will only open the amount demanded by the engine so being over-carbureted will not be an issue. When rebuilding these carbs, be extremely cautious in tightening the fuel discharge nozzles as warpage can occur if over-tightening the single screw that holds those in place.  Check the gasket flange for the discharge nozzles for straightness when you have them removed from the carb to save you some grief later.  Leave the jetting stock when first using these and then adjust accordingly if needed. By KULTULZ - Last Month Being a vacuum secondary carburetor, the secondaries will only open the amount demanded by the engine so being over-carbureted will not be an issue. THANX TED! As usual, your knowledge and experience(s) far out-weigh mine. The flow ratings were posted by a guy that was tired of hearing the 600CFM fantasy (other than the 1.19) and gathered up some he had laying around and had them professionally flow bench tested. By dennis22 - Last Month Thanks KULTULZ for the cfm pic. Thanks Ted for the info. I’ll check for the 1.12 cast mark, if I can see it. Looks like it hasn’t been used since 1962🤣. And I’ll be sure to re-read this when disassembling.