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I currently have a 68 coupe with a holley model 4160 750 CFM vacuum secondary manual choke carb (list #3310-6) attached to a 289 engine that was bored out to a 302, with automatic transmission. While trying to figure out why my car was dying when it wasn't heated up, I soon discovered that my choke is a manual, with no control cable connected to it, meaning that the choke was always open.

My question is this: since, to the best of my knowledge, the 68 was never fitted with a space for a manual choke cable, should I drill a hole and connect a control cable, or just convert the carb to electric operation? I don't know the pros and cons of either, so information regarding that would help as well. Also, how big a job is conversion versus the drilling and mounting of a control cable? Is one way easier/better/more reliable than the other?

Also, I am aware that a 750 cfm carb is slightly large for a 302 automatic, however I am reluctant to buy a new carb due to my complete lack of the money required to purchase one. How bad is it to have a large carb? What kind of problems would I have? Do I NEED a smaller carb, or will it just be a gas issue, or are there other things that I don't know about?
 

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You might already have a metal cutout that you need just to pop out to have the choke hole in your firewall. I'm not sure on the 68, but Mustang, being a mass produced car with multiple configurations, has holes, plugs, screw holes and wiring pigtails that would allow you to put nearly any option that was original to your year on your particular car. This means that if a manual choke was offered on your car (IIRC, the 67 HiPo was the last year with a manual choke, but I could be wrong--I just don't know 68 and later like I do the earlier years), you would have a cut-out you would just pop out. This is the case with AC--I had a 67 with the cut-outs still in place, and to add AC, I just popped them out to route the hoses. I'm rambling...
If I were you, I'd convert to an electric choke. It's not that complicated or expensive (not sure on Holleys, but you might find a compatible choke equiped carb in a wrecking yard in which case you could get all the conversion parts).
A 750CFM carb is a bit big (you need only 600CFM max), but only if you open it up all the way. ;)
Daniel
 
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i have a 600 cfm dp 4150/4160 on the 5.0L in my 65. i just wired the choke wide open and let it warm up before i take off. not a real problem in CA, but it gets real cold where you live, i'de put an electric choke on it.
 

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If you like poor gas mileage, poor low end performance you run a 750 on a 302 Gary
 

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You can use your 750cfm on your 302, since money is an issue. I agree that if you were to buy carb, 600Vac would be most versatile choice to mildly modified 302. When I swapped 750cfm to 600cfm Vac, I didn't notice any improvement with low-rpm responsiveness. MPG will be better with 600, but a lot depends on main and secondary jet sizes and vacuum secondary spring. Vacuum secondaries do not open unless needed. I would use manual choke, but when I bought my speed shop clearance sale 600Vac, it had an electric choke and I haven't bothered the conversion.
 
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