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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.
holy C*ap you put a bored out 460 in a fox body that must of been a beast must of had a fun time getting it shoe horned in there that would of been pretty bad A$$
dont look at me, i build cars to drive not to show. i also dont like two barrel carbs, unless you have three of them on the same engine.
Quote:
Originally Posted by GTOlover
holy C*ap you put a bored out 460 in a fox body that must of been a beast must of had a fun time getting it shoe horned in there that would of been pretty bad A$$
a 460 powered fox body is not hard to do, in fact a company called kaufman products used to have a complete swap kit, and even ford sells mounts and an oil pan through their motorsports program, or at least they used to.
big block fox bodies are like kids who grew up in neighborhoods where you played frisbee with manhole covers
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.
Given your input, I'd say a 350 cfm carb is probably all the bigger you really need to go.
holy C*ap you put a bored out 460 in a fox body that must of been a beast must of had a fun time getting it shoe horned in there that would of been pretty bad A$$
Quote:
Originally Posted by rbohm
big block fox bodies are like kids who grew up in neighborhoods where you played frisbee with manhole covers
Lol! Yeah, even with the 2.73 rear end ratio, it'd accellerate hard enough to doppler shift the light around you! hehehe. Ok, it felt that fast. Built a 460 powered Fox Capri drag car and thought it'd be fun to do the same with an autocross style car for going around corners with that much engine. Not hard to get the engine in there, and the Global West suspension bits were helpful, but the brakes at the time simply sucked, even with sticky tires. Still, it could pull right at 1G with the A008 RS II street tires.
Wish I had better pics of it:
This was before removing the factory Cobra stripes (started life as a 2.3 turbo car). Not real pretty, but real evil. I may have to build another...
OK guys...lets destroy the myth of "too much carburator". It's what mechanics say that don't know how to tune carbs. This has been proven to be false again and again, not only at car-guy type internet sites, but I am happy to see that even CarCraft and those magazines no longer buy into that.
But you also have the contrasting myth of "more is better" - over cam, over carb. It's confusing. UNTUNED - too much carb will give you performance problems. TUNED - any carb can be made to work.
It all comes down to tuning. Now a vacuum carb will only flow as much air as you give it anyways, "too much carb" is not applicable. It might not need that much flow, but it won't hurt having too much carb (but it might not help either). Chevy used 750's on their smog-suffocating pre-EFI small block cars of the 70's.
Now a mechanical carb, that's another story, but you can tune it to fit. I've read of 1100 carbs on 350 small blocks. I myself have a 750 holley double pumper on my '80 vette, I moved up from a 650, absolutely no negative impact to low RPM driveability or idle. Now my car is not stock - I have heads and manifold that flow like crazy, but It could be made to work if my car was stock. BUT I carefully tuned it up, including changing jets and shooters, tuned my timing, etc.
Now, there are sites that can estimate how much carb you need based on your size engine, top RPM etc, and they come in handy if you really want to stick to the out-of-the box setting for a carb. It might be best for you or someone without mechanical knowledge. But any large carb will work, given the right settings, and I personally think the issues you relate are not related to the carb, or it is related to an improperly tuned carb.
Lol! Yeah, even with the 2.73 rear end ratio, it'd accellerate hard enough to doppler shift the light around you! hehehe. Ok, it felt that fast. Built a 460 powered Fox Capri drag car and thought it'd be fun to do the same with an autocross style car for going around corners with that much engine. Not hard to get the engine in there, and the Global West suspension bits were helpful, but the brakes at the time simply sucked, even with sticky tires. Still, it could pull right at 1G with the A008 RS II street tires.
Wish I had better pics of it:
This was before removing the factory Cobra stripes (started life as a 2.3 turbo car). Not real pretty, but real evil. I may have to build another...
I would love to do a build like that with a 87-93 mustang coupe put in a 460 and back it with a T-56 with a ford 9 inch and set of 4.11's and some suspension tweaks & upgrades and a set of sticky tires
Chevy used 750's on their smog-suffocating pre-EFI small block cars of the 70's.
Right they did, but also they used Quadrajets and if you've ever looked at one, you will notice they had small primaries and really big secondaries. Compare that to most Holleys which have the same size primaries and secondaries. The Quadrajets with their smaller primaries made them a really good street carb for the low performance dog engines of the 1970's and the secondaries were probably a bit of an overkill but not really enough to notice, at least in my experience, though I know some people dubbed the Quadrajets as a "Quadrabog".
Given your input, I'd say a 350 cfm carb is probably all the bigger you really need to go.
Don't get me wrong, we will drive it more, but it will be pretty leisurely. Last fall was spent learning how to drive a manual. This spring we would have been driving it more, but weren't sure why it was acting the way it was. Of course, both times it did this was on that short drive to and from work. So, that is what lead us to having it looked at and the opinion I received in my original post. Some seem to agree, and some don't. From what I gather, taking from garage to garage might gather a variety of opinions and I don't want to rack up $ just having it looked at. Hmmm.... Just deciding which route to go. Tune the current carb, replace it with a lower cfm... At least I'm learning a lot.
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 was pointed out earlier, the majority of techs working today know all about fuel injection and very little about carburetors. If you can, take your time and do a little research until you find a mechanic who was around back in the carb days and have them take a look at it. Holleys are simple to work on and it may be that a simple float adjustment will take care of it. In fact, there were only a few carburetors that were a real pain in the butt to work on. (Mikunis and Ford's variable venturi come to mind)
Do you have a dragstrip nearby or know anyone who drag races? Might be a good place to scout for a good old school carb guy. Good luck
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