466,9.5 comp,hyd flat tappet 224-230 @ .050 525-544 lift 110lc,d3ve ported heads 2.19-1.71 valves,comp magnum roller rockers,matched stealth intake,1 3/4 headers,3' exhaust,msd billet dist,c-6,2200 stall,3.50 gear,3850lbs-what size carb???

 

Assuming a few things.....
Its a street vehicle
Max RPM (reality) 5500
You are running a good exhaust system (other than OEM)

If running a 4V carb, I calculate 567 CFM, so a 600-650 would be fine.

If running a 2V carb, I calulate 934 CFM, so two 500 cfm units would be fine.

With an automatic, I would highly suggest vaccume secondaries.

I also figure the volumetric efficiency at 90%, which is a little high for street engines (which is typically 80-85%), because I would rather have a carb that has the potential to be slightly rich versus slightly lean........much easier to tune down than to tune up in most cases.

The formula is...

CID x MAX RPM x Volumetric efficiency (.90) divided by 3456 (barometric pressure)

2V carbs, you must multiply the CFM by 1.4 since their CFM is calculated a little differently.

 

using the formula gives 667 cfm.... try a 750 cfm vac secondary

 

i was thinking 750 dp-5800 max-i've always gone to the next biggest size-the formula is just ballpark-it's always too small-i had a 351w with a 650 called for 647 and it was a major dog tuned,swapped on a 750 same carb,untuned-felt like i bolted on 100 hp-when i asked about carb size-i'm hoping someone on here has a similar combo-not an obvious guestimated formula that doesn't mean anything

 

The formula is never to small, it's exactly what any given size engine can use at a given rpm.
But since you're obviously so smart, why don't you use what you want?

 

You haven't a clue of what you are talking about. Seat of the pants is never, ever a performance indicator. Time slips or dyno sheet, but your butt is not a tool that can be relied on. You and youradvise are the reason so many guy have bad running cars. Back when I ran for pinks, you and guys like you we so easy it was almost not fun.

 

ok so i guess going by the formula method-a 200hp motor-same cid that makes peak power at the same rpm-other motor being heads,cam,intake and makes 350 hp i guess they will require the same size carb-that makes perfect sense

 

not in the case of the 200hp vs 350hp motor. The formula calculates the maximum amount of air an engine can use, if it's 100% efficient. The 350 hp motor with the same cid as the 200hp motor , is more efficient, meaning it uses more air than the 200hp motor. The 350 hp motor may be 90% efficient, the 200 hp motor only 75%.
Look at it this way, an engine is nothing more than an air pump. Every time the engine roates it sucks as much air in as the volume of the cylinders. Intake, valve size, cam etc, restrict the airflow, so in reality an engine never fills the cylinders with all the air it could, because in the short amount of time the valev is open, there isn't enough air flow to fill the cylinder completely. The better your intake runners, valves and cam are, the closer you get to being 100% efficient, but you never get there completely.
Your 466 cid motor can only suck in 782 cfm a minute at 5800 rpm. And that's if it were 100% efficient. You can easily take 10% of that.

Carb size is dictated by engine size and rpm. All the other add ons just try to get you closer to 100%, but you will never exceed 100% fill volume, unless you're running a turbo or a supercharger and force more air in.
I hope that explains things a bit.

 

all i was saying is you round up and not down-782=800 not 750,to go by the formula is just a guestimate since more engine airflow-better induction requires more fuel and the equation does not take that into consideration-and yes i ran my car at the track and went from 11.21 @ 122 to 10.98 @ 124 N/A i did was changed the carb and the formula calculated 671-went from a 650 to 750 no other changes-so i guess that makes me an idiot to have a slow 10 sec car and pick up that much by Assuming i need a bigger carb-by the way i'm not trying to be a jerk but if people like Bear and TX call me a moron for trying to disagree with someones opinion or calculation than whatever-i always go by proven combinations because this is the real world-so you two can be a bunch of know it alls with junk i could care less cause my **** runs good

 

i'd use a 750 double pumper or an 850.i had a 950 on a .060 over 460 and it was fine.i'd use a little more converter than that too,maybe 2500-2700 stall.

don't know what everybody is so excited about.usually everybody tries to help on here.calm down.

 

Using a double pumper on anything other than a full out race truck shows how little you know about engines and preformance. Even Holley, who would rather sell you the more expensive D/P carb says don't do it. Do you see a pattern here? Unless you are winning races you should realize that a street truck doesn't equal a pony car and what you can do with the motor in it.

 

well bear you obviously do whatever you hear based on opinions-i go by what wins races and how my vehicle performs best. i will only run a dp holley-it outperforms edelbrock or vac carbs on any motor i have had and tuned properly will out mpg it too

 

guess we all should quit replying to questions on here in hopes you will enlighten us with your wisdom.don't know what is up with the attitudes on here.the guy asked a simple question for peoples opinion on a set-up and you all jump down his throat.you guys should appologize.

you don't know me and i could care less what you have to say.i am just trying to help a little.

 

I agree double pumper is not necessary. And yes you are wrong that carb is going to be too big and your truck is going to run like crap. My buddy just bought a 79 350 with a pretty serious 460 the guy before him sold it because he was an idiot and threw a 850 demon double pumper on it. I gave him my edelbrock 650 and tuned it for him and now he has more power, runs the way it should and has good power from idle up. and that motor dynod at 450 horse.

 

When others enlighten people with proven BS, then they need to be called on it. Opinions don't make motors run better, proven performance procedures do. How many championship winning motors have you built?