I have a 1965 Mustang with a 289 (I believe the engine is actually from a 1967). I a stock C4 transmission & but have an updated aftermarket dual exhaust (non header). I would like to open the motor by adding a 4B carb and manifold. On e-Bay I can see a KMJ Performance SBF dual plane aluminum intake manifold for about $150 (shipped). I am not sure which carb to use....guessing a Holley 600CFM? Can anyone tell me which model #? Is there any other solution you would recommend? Are there any other tips/tricks to use or traps to avoid? My first post ever to the forum...BIG thanks from the rookie!
Yes, the heads are stock. My dad bought the car new in 1965 and my brother drove the car in the '70's. He blew up the engine and replaced it with another (think it was a '67 because the valve covers were blue). I am also considering an electronic ignition. My plan is to keep the car as "stock" as possible while boosting the performance. I have kept all the origional parts in case I ever want to take it back to origional shape. Thanks!
depends on what your looking for a 500 holey would be fine. there is a formula that you can use to determine the right carb. you can have a 1000cfm carb and it would act just like a 500cfm there is only so much gas you can get into the ports and valve and so much air fuel mixture you can get into the cylinders i just looked it up with a stock engine youd be fine at around 440cfm carb at 5000rpms if you go 6000rpms a 500cfm carb would do just fine once you get into bigger valves more displacent higher lift cam and blowers you put on a biger carb
a stock engine you arent going to see dramatic efects be sides it burns more fuel. you want more power change the heads and the cam. but for now a 500cfm woul do fine in my opinion.
If you plan on doing any serious mods, use a 550-600 cfm Holley. I know, my sig says I have a 750 cfm Edelbrock. Shut up. I was sixteen when I bought it and didn't know any better. A smaller carb will respond better than a larger one when properly tuned.
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Proud owner of a '65 289 coupe w/ C4. Equipped with Edelbrock Performer intake K&N air filter, and 600 cfm carb, Comp Cams Xtreme Energy valvetrain, Comp Cams XE262H cam, MSD ignition, and ported heads. Suspended by 600# 1" drop front and stock rear springs, KYB shocks, 1" front and 7/8" rear sway bars, and Traction Master style traction bars. Your friendly suspension kid.
If you plan on doing any serious mods, use a 550-600 cfm Holley. I know, my sig says I have a 750 cfm Edelbrock. Shut up. I was sixteen when I bought it and didn't know any better. A smaller carb will respond better than a larger one when properly tuned.
Hello. Don't feel bad. Many, many people think that a bigger carb is automatically better. I ran a little hands-on test on a K code that I used to have. I put a 600cfm Holley on it and drove it around, flogged it, etc... for a while, and then I put a 480cfm Autolite carb on it and didn't change anything else, and it ran better with the 480. I realize that 'runs better' is kind of vague, so, to dial that in a little better, the car was quicker off the line, more responsive, and got better gas mileage. It ran just fine with 600, but, it was almost like efi with the 480 as far as throttle response.
I agree with Veronica about the 480cfm Autolite. I replaced my stock iron 4-bbl intake with the aftermarket Cobra high rise and kept the 480 on it instead of changing over to the Holley. I actually had to lean the mixture because it was running too rich and it still has enough to feed a hipo cam. And I hear that you can actually get around 18-21 mpg with them if they are tuned right. That's if you don't kick in the secondaries too much . We all know how hard it is not to do that.
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1967 Mustang Fastback
Acapulco Blue
289 HP bored .30 over
PA C4 transmission
A work in progress...
All, I have a similar question on changing out my original 2 bbl carb for a 4 bbl. I own a daily driver stock '66 coupe 289 w/ C4 automatic. It's got the original carb on it, but the carb is in need of some TLC. I've heard that upgrading to a 4 bbl would give me a little more off the line power and might actually save on mpg. Is that a myth? I'm less worried about higher mpg than I am about a little more power.
the 2-4 bbl swap is a power upgrade for sure but not a gas saver :P....i went from about 17 mpg with my stock 2 bbl down to the 11 or 12 range with the 600cfm....i wouldn't go much bigger then a 600 though my buddy has a 67 he slapped a 700cfm on it and it floods if u stomp on it...which i would believe is rather embarrassing if you were to flood it in public. i bought edelbrock i love the thing pulled it out of the box and only thing i ever did was turn the choke off in the summer except for that no work or maintance neccesary i think they are best out of the box
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1965 candy apple red 289 with 4bbl along with chrome accents
Pitfalls........I can think of only one which may occur, and is well documented here in previous posts: the oil pump driveshaft falling down into the pan when the distributor is removed. There is a search feature on these forums, it might be good to look up some of the older threads and see what folks have to say.
Since the engine was replaced some time ago this may or may not happen to you; I believe the more, um, "seasoned" engines are at a greater risk of this happening. Not the end of the world, as there are solutions to it. I must admit it has kept me from upgrading to that 4100 I have tucked away; my engine has never been apart and I just KNOW that driveshaft is waiting to fall...........
Michael
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1966 289-2V C-4 Convertible. All original drivetrain. Factory center console and power top. Dual res. MC and power brake upgrade. Rust bucket brought back to life, I am the 2nd owner of "Lucy".
1990 GT 25th Anniversary 5.0 AOD Convertible. Dynomax cat-back, K&N, the usual crap. Welded in subframes, welded in reinforcement plates (Ford riveted them in. Go Ford! )New engine and transmission. Date coded radiator hoses. Second owner of "Katie".
1966 289-2V C-4 Convertible. All original drivetrain. Factory center console and power top. Dual res. MC and power brake upgrade. Rust bucket brought back to life, I am the 2nd owner of "Lucy".
1990 GT 25th Anniversary 5.0 AOD Convertible. Dynomax cat-back, K&N, the usual crap. Welded in subframes, welded in reinforcement plates (Ford riveted them in. Go Ford! )New engine and transmission. Date coded radiator hoses. Second owner of "Katie".
I have 2 comments
1. Veronica's experience with the K motor, I did the exact same thing with the same results on a K motor also
2. In my 30 years of working on fords (small blocks in particular)only once has the oil pump driveshaft fallen
I say go for it but i would personally stay away from a Holley carb
I have had leakage issues with them after a few years .
My recommendation if you can is to go with the Autolite 4100
Replacing 289 2B carb with 4B carb? 
Don't feel bad. Many, many people think that a bigger carb is automatically better. I ran a little hands-on test on a K code that I used to have. I put a 600cfm Holley on it and drove it around, flogged it, etc... for a while, and then I put a 480cfm Autolite carb on it and didn't change anything else, and it ran better with the 480. I realize that 'runs better' is kind of vague, so, to dial that in a little better, the car was quicker off the line, more responsive, and got better gas mileage. It ran just fine with 600, but, it was almost like efi with the 480 as far as throttle response. 
. We all know how hard it is not to do that.
)New engine and transmission. Date coded radiator hoses. Second owner of "Katie".
