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302CI Build - What's Your Problem?

Carb Question

Ed Tucker, Bel Alton, MD: Let me say that I am not what you would call experienced in auto mechanics. I can do more than the average person these days, but I'm not the total-rebuild kind of guy...yet. That's one of the reasons I like your magazine; it gives step-by-step instructions to dummies like me so even we can make things happen!

I have a '73 Mustang Mach I with a 351 Cleveland engine that is in very good shape-it has fewer than 60,000 original miles, and I have had to do very few repairs on it-it's a real numbers-matching car. The problem is the carburetor. Over the years, the gaskets and other parts have worn out or dried and cracked so that the carb leaks fuel onto the intake. This is not good, especially since my wife is the primary driver of this car. No one seems to know what carb I can replace the old one with. This is the factory Ford carb, and I would like to replace it with a Holley or Edelbrock carb that will be a simple swap. I'm thinking around 650 cfm. I have called all over the states talking to Ford techs and lots of auto-part and dealership people, and no one can tell me what to replace the old carb with. I really want to get this ride back on the street. Can you please tell me what carb will replace the original factory four-barrel?

Jeff Smith: We did a little digging, and it appears that your engine came equipped with an Autolite 4300 version carburetor of 600-cfm capacity, but this carb could be either a square-flange or a spreadbore design (like a Q-jet style). We're going to assume that your difficulty in finding a replacement is because you have the spreadbore style of the Autolite carb.

According to our pal Sean Murphy at Sean Murphy Induction, there is no Holley carb that will directly replace the stock spreadbore unit that also incorporates the kick-down linkage for the automatic transmission (we're assuming also that this is an automatic). While you could use an adapter between the intake and a standard-flange Holley, that might stuff the air cleaner into the hood.

Murphy says he won't even attempt to rebuild those original Autolite carbs because they warp and leak very easily and are basically "a crappy design." His suggestion is to yank the original intake and carb and replace it with an Edelbrock Performer for the Cleveland 4V (PN 2665, $184.88 summitracing.com). This allows using the much more popular square-flange Holley carburetor, but the manifold is drilled for both carburetor bolt patterns. If you choose to stick with Edelbrock for the carburetor, the Performer 600-cfm electric choke version (PN 1406, $264.95, summitracing.com) is a great choice. You will also need the Edelbrock throttle add-on adapter for the automatic transmission (PN 1483, $14.88 summitracing.com).

If you would rather go with a Holley universal-replacement carburetor, the company offers the 0-80457S 4160-style, vacuum-secondary carb with the Ford linkage and an electric choke that's a great fit for the Cleveland. We found it for $269.99 at gofastparts.com. Several more Holley square-flange carbs are available all the way down to the universal 0-1850-style carb with a manual choke. Of course, if all this is a bit more money than you wanted to spend, you could search the swap meets and eBay for a used intake. A used vacuum-secondary 600-cfm Holley should be easy to find. Good luck.

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