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on the "horn" of the carb, there will be numbers stamped in. this is when you take the air cleaner completely off, and look at the carb from the front of the engine. These numbers will be stamped in the flat "wall" facing th efron of the car. What numbers are stamped in there? I really am thinking todays gas has gotten it ouut of tune and rejetting the primary side would be in order, but not until float level is checked and also check for any gasket leaks, either gas leaking or air leak. Use a fine mist spay bottle, and with the engine running, spray the water around the base of the carb slowly. if the engine tone changes, you have a gasket leak. Very common for old gaskets.
AS FOR THE 480 AUOTLITE CARB being best, not for most! It's only after the many mods made that they have out performed other carbs. Clearly if you got the coin, the man listed before knows what he's doing. But most people will get better performance with a 600 to 670 cfm carb.
Carb sizing formulas are of little use in real world because of the efficiency of every engine and type of driving. Formulas are based on 100 percent efficient, as opposed to most engines never run better than 65 percent efficient.
Let us know what the numbers are on the carb, and we can help you from there. Various series of Holley carbs have different things to address. I would look also to see if your fuel cam is the pink or dark brown one in the right holes on your throttle positions. But without knowing which carb, I can not point you in the right direction to get it exact.
I can have the float levels checked. It has not backfired.
It currently has an electric choke.
Quote:
Originally Posted by rbohm
let me correct you here, the C code 289's came with a 350cfm 2bbl carb, the A code 289's came with the 480cfm 4bbl carb.
look at the vin number, in the 5th or 6th position, i forget which one off hand, you will see an alpha code, t for a 170 inline six, u for a 200 inline six, c for a 2bbl 289, a for a 4bbl 289, and k for the high performance 289.
as for your problem, check the float levels, holleys tend to run a bit high with age. also has the engine backfired at all recently? perhaps more than once? if so its possible that the power valve has been blown. they are easy to replace. as for the choke issue, if you dont have an electric choke, there is a kit available to install one, i think it runs like $50 or so. when you adjust the choke, start by adjusting it until is is off even when the engine is cold, and then adjust it back the other way until the choke plate just closes.
Typically, not very high. When we drive it it has been to work (about 1.5 miles on a 35 mph street), or my son's baseball games (maybe 45 mph with stop signs and lights). Pretty much suburban driving. No hot rodding needed.
Quote:
Originally Posted by Deez Nuttz
You didn't mention more about the car....how many rpms does this thing typically see?
To determine what carb you need, IIRC it's the cubic inches X engine rpm divided by 3456. A 289 spinning no more than 4400 rpm only needs a 368 cfm carb to work right.
If your Mustang is a typical cruising street car, it probably doesn't ever really see 4400 rpms unless your foot is planted in the pedal taking off from a stop light or if it's a manual and you're shifting it past 4400.
The two biggest hot rodder mistakes: over camming and over carbing.
On a drive of 1.5 miles, it's probably hardly even getting hot enough for the choke to switch off.
Try taking a more scenic route.
Or take it out for a little blast every so often, get it up to freeway speeds for a quarter hour or so.
I think it might just need it's tubes cleaned out.
Quote:
Originally Posted by tgbwc
Typically, not very high. When we drive it it has been to work (about 1.5 miles on a 35 mph street), or my son's baseball games (maybe 45 mph with stop signs and lights). Pretty much suburban driving. No hot rodding needed.
You didn't mention more about the car....how many rpms does this thing typically see?
To determine what carb you need, IIRC it's the cubic inches X engine rpm divided by 3456. A 289 spinning no more than 4400 rpm only needs a 368 cfm carb to work right.
If your Mustang is a typical cruising street car, it probably doesn't ever really see 4400 rpms unless your foot is planted in the pedal taking off from a stop light or if it's a manual and you're shifting it past 4400.
The two biggest hot rodder mistakes: over camming and over carbing.
To throw another log onto the fire...
when building up Ford dual purpose street/autocross/road race engines, gger turned out to be better. Fords love carb. the Edelbrock street replacemtn carb for a 302 was a 700 cfm unit, and even it wasn't big enough for my street engine. My 302 (bored to 306) with 10.5:1 compression and a dual plane manifold wouldnt' run on a stock sized carb, the 700 cfm unit was better, but it still wouldnt' run at WOT, no matter how it was jetted. Didn't come alive until a modded 800 cfm Holley was installed, even though none of the "formulas" recommended anything bigger than a 600, even at 7500 rpm. Well, it took an 800 that had ben modded to flow almost 900 cfm before it would run right. And then it ran clean at any throttle setting on the track OR on the street. Go figure:
After the modded Holley was installed, not only would it run properly at WOT, it also was able to corner at 1+ g without stumbling, and managed to knock back over 20 mpg on the highway even with 4:10 rear gears and 23" tall tires.
Same thing on my 466 cid engine in a Fox Mustang. it needed way more carb than recommended to run smoothly and properly.
My model A street rod has a 350 SBC with weiand tunnel ram and dual 600 holleys (single pumpers). Engine isn't anywhere close to stock though.
We struggled with idle performance (like the op) but not highway driving or higher RPM performance. We played with jets, float levels, timing, etc etc etc. It wasn't until years later when I was looking at performance charts for tunnel rams that I realized why it could be that we were having trouble idling. Without getting into detail it seems that tunnel rams are not well suited for just poking around. They look cool.....and they perform well when you're wide open.....but not so much when you're just loafing around town.
One of these days I may experiment with it and just put on a single carb manifold with a 750 and see what kind of difference it makes.
On a drive of 1.5 miles, it's probably hardly even getting hot enough for the choke to switch off.
Try taking a more scenic route.
Or take it out for a little blast every so often, get it up to freeway speeds for a quarter hour or so.
I think it might just need it's tubes cleaned out.
That's just my trip to work and I have only taken it there a couple of times.
We will take it out for more drives. That's what we want to do. I just want to make sure it is going to be reliable for us. We just got it last August and didn't drive it much in the fall. Brought it back out this March and started driving it in May. That's when it was acting this way.
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i have
Some guys win all the trophies!
