What size carburetor do i need for a 400. Jun 14, 2017 · New to this forum.

What size carburetor do i need for a 400. What Size Carburetor Do I Need? By Jason Lubken. 6 that’s a 460 bord 30 over with a mid sized cam 600cfm carb high rise intake what size mechanical fuel pump do I need Reply Roland says: Dec 27, 2020 · This combination of parts will likely not break 400 hp. , released (intentionally or negligently) into the world in 2019 (VOWL-19) Ten trillion to start with, increasing as What size Carburetor do I need? (496 stroker build) Started by TXcharger70, September 29, 2010, 02:00:23 PM Are you using a 400 block with a 4. Another carb post. With this number, I would go with a 650 to 750 cfm carb. Is 7000 CFM good? 7000 CFM is an extremely high airflow rating and is typically not used in automotive May 18, 2024 · In summary, the size of the carburetor needed for a 350 Chevy engine is determined by the engine’s displacement and expected RPM, with general recommendations pointing towards a 600 cfm carburetor for a 350 by 5500 RPM and a 650 to 700 cfm carburetor for a maximum of 6500 RPM. 2. May 26, 2017 · Need a good carb recommended for a Pontiac 400 . Jul 18, 2024 · What size carburetor do I need for a 400 hp engine? For a 400 hp engine, the right carburetor size depends on the engine’s size, RPM, and use. It might make the most overall power. Identify How Much Carb You Need. 1050 dominator carburetor 720 HP do i need too go 2 750 or 850 carburetor. A 600-650 CFM carburetor is a good start for a naturally-aspirated 400 hp engine. 2 cfm however, since the engine is a 4 stroke the 400 ci discplacement occurs every two crankshaft revolutions, so divide the above by 2 and you get 677. Jul 15, 2024 · With our carburetor cfm calculator, we will prevent you from ruining your engine. We’re here to help! Feb 27, 2017 · Then, take 1,920,000 and divide this number by 3,456 rpm and get 557 cfm, which calls for a 600-cfm carburetor if you're planning 5,500-6,000 rpm. Do you really understand what your carburetor needs to be in order for your engine to be happy? Let us explain the details you need to now before you choose your next Holley carburetor! Apr 21, 2008 · (Drilling a carb spacer should work OK if the carb throttle body doesn't have a suitable port. However, for racing or high-performance applications, a larger carburetor with 850+ cfm will perform better. Apr 19, 2009 · I have set up many carbs on Pontiac 400's and your current carb size is good for your combo. How much horsepower will a 750 CFM carb support? Jul 5, 2004 · With your gearing your 400 will do just fine with a 750 DP. Aug 3, 2003 · As an example, consider a 400cc motor. You’re not going to need much more than 600 to 650 cfm. i. Using the rule for various engine sizes, I get. If you just think bigger is better then why not 850. Includes a rich graphical interface to visulize the output. I have an Edelbrock RPM Performer intake on it, and the rest is basically stock. 400 cc = 40 mm. A 650 will fall flat on its face at 5,000 It's much more difficult to "over carb" or "over cam" a Pontiac 400 than most other engine families. Therefore, 650 CFM also does well with 400 small blocks. As a general guideline, engines under 50cc may use a carburetor with a size of 10-15mm, while engines over 1000cc may require a carburetor with a size of 48mm or larger. Jun 2, 2008 · The 400 probably doesn't loose nearly as much as a 455 engine, put is still pulling pretty hard on the intake/cylinder head runners. It has a mild cam. Right now the car stalls out when I put it in gear. It appers that i might have 2 symptoms related to that, first, the old men i bought the quad of had left 1/2 tank full, this might be old gas and as you mention micro particles must of got stock or clogg near jets or carb moving system, second and this is my fault, the fuel tank selector was engaged on Reserve Jul 20, 2008 · The only other possible future upgrade would be a larger cam to give it a muscle car rough idle. Aug 26, 2008 · I'm confused on which carb to go with. It runs mid 13 second quarters with a best ever of 13. What size do you think i need? 460 30 over, 500 lift cam stock heads weiand stealth intake, Headers, etc. This tool will help calculate the size carb you need in CFM for stock or racing engines. Find the recommended carburetor size for your engine using the carburetor CFM calculator, plus see the formula for finding the idea carb CFM. Carburetor CFM. Any replies would be great. A properly sized carb will have good low end, and rev plenty for a streetable truck. Thanks Dan Feb 5, 2010 · The size of carb(s) or CFM required for a given application can be calculated by the following formula A: {(CID x RPM) ÷ 3456} x {Boost ÷ 14. Q-jet, Holley, Edelbrock, Demon, which would work the best for my combination? I would like to end up with something around 400 hp and 400 torque if possible. 030 over, 11:25 comp, factory rect port heads 3919840 with some porting job, factory high rise rectangular port manifold (the one with the snow flake mark), Lunati hydraulic roller cam, basic operating range 2600-6800 RPM , intake duration at 050 inch lift is 241, exhaust duration at 050 inch lift is 249, advertised duration 292 Sep 9, 2024 · Engine Size (ci): Carburetor Size (cfm): Up to 400: 600-750. Engines that have been tuned for improved performance or have a stronger performance camshaft and valve combination may have up to 90%. If it were 6,500 rpm the Summit racing website online chart calculator has 508 cfm. A smaller carb will help low end but kill top end. But then again we don't how you built up the 350 Oct 28, 2018 · I ran my old truck at the dragstrip today. S. carb would probably get better mileage, but your RPMs will come up a lot faster with the DP. The mechanic says the 670 carburetor is too small on my LA 360 engine. If the plan is to take the 400 over 6,000, you need 700 to 750 cfm. Complete Quick Fuel Carburetor Catalog Nov 12, 2020 · What size carburetor should I be using on my LA 360 engine? Right now I have a 670 Holley carburetor. Oct 1, 2023 · What size blow thru carb do I need? The size of the blow-through carburetor you need depends on various factors, including your engine’s displacement, desired horsepower, boost level, and other modifications. Grey line is EXAMPLE described below CARBURETOR SIZE – CFM B C 3000 500 400 300 200 600 650 700 750 800 850 1050 2500 2000 1500 1000 500 INSTRUCTIONS 1. 30 over with a ram air iv 9794041 cam and #16 heads with mild porting. Apr 16, 2009 · Hi Delbert, tx for looping me to all the possible causes of fuel related problems. The square root of 400 is 20. You will note that agrees nicely with the FCR-39 that is common on 400's. 100 cc = 20 mm. 6/30/2016. 850 to much if stock or close to stock. Oct 1, 2023 · The size of carburetor you need depends on factors such as engine size, application (street or racing), and other modifications. What size carburetor do I need for a 400? The best size carburetor that you need for a 400 is a 600CFM and 4-barrel carburetor for SBC 400. Thanks for your report on your experience. Select engine size (cubic Nov 19, 2019 · Don't just take your brother or your friend's advice and jam the biggest carb you can find onto your engine. A common range for a blow-through carburetor might be between 650 and 850 CFM, but it can vary significantly. May 10, 2019 · Normally, I would say the 650 DP, but given the gears, I wonder about the 750. What carb/ cfm do you guys recommend ? I have a local guy who is very good at rebuilding AFBs & AVSs if I need to buy a used one. Select minimum RPM at wide-open throttle in col-umn A; this will be converter stall speed on cars with automatic transmissions. Aug 29, 2007 · Which do you enter in the calculator? Another pet peeve of mine is the nitpicking over 50cfm of carb potential, as in "should I use a 650 cfm or a 700 cfm carb"? The carb setup is as important as the size, the ability of it to get the right mix of fuel and air into the intake in a timely manner overshadows other considerations. Jan 8, 2004 · Fuel Injection, Carburetion & Fuel System - 351M to 400 = different carb size? - I have rebuilt my '78 351M into a 400 and am planning on using the same 2 barrel intake and carb. d. B. 1 compression, 480ish lift cam, stock intake. Nov 8, 2022 · What you should do is take a look at gph rating of the pressure the carb needs, like around 6 psi. Save Share Like. What changes do I need to make to the carb that was running on a 351 cu motor but now will need to feed 400 cubes? Feb 21, 2013 · so I been looking to get a new carb for a while but haven't found anything good Now my question is my buddy had a 01 500 scrambler with mikuni tm flatslide carb He not sure off the size but it ran great on his atv I wondering if anyone knows if that carb is meant for the 500 I haven't been able to find much about it. After looking around, I don't think there a whole lot that I do plan on doing with the motor. Cliff _____ Mar 14, 2017 · On the other hand if your 400 horse 350 got there with modern Vortec style heads and a cam like the Comp XE268H you don't really need a lot of tunability from the carb. -SM Feb 13, 2017 · The formula below will help you determine the correct size carbs for any blown application. The carb that was on there before was a edelbrock 1805 650 cfm carb manual choke. Nov 18, 2020 · To arrive at the most appropriate carburetor choice, there's a basic formula: engine displacement multiplied by maximum rpm divided by 3,456. 060, ~125 open chamber heads with +38cc dome pistons, Howard's cam (120031-12), performer rpm intake, pertronix small cap distributor, th400, 3. P. Feb 18, 2024 · The cam profile also affects the carburetor selection, as does valve overlap and valve lift. Automatically and instantly get a near perfect result for the correct main and pilot jets based on your bike modifications, aftermarket exhausts, pod filters, altitude, ambient temperature etc. Share. 1 cfm as the 'theoretical' air-pumping capability of your engine. LEON. 5" the carb is too small if it's less than 1" it's too big. It ensures that fuel is delivered at the right rate to match the engine’s power requirements, improving efficiency and fuel economy while minimizing emissions. It is a small block 400 with stock 400 heads, stock low compression pistons, performer intake, Holley spreadbore carburetor, thumper cam, and cheap headers. Add Article To List. Another rule of thumb is that you need 10 actual gph at working pressure to ensure sufficient fuel supply for 100 hp. But, it’s best to use a sizing calculator or get expert advice for your exact needs. The Holley tech says use a Street Avenger 670 or a 0-3310c 750cfm (both vac sec), BG recommends a 1402020 Speed Demon 750, and AED recommends their 750HO. 401-450: 750-850. “What size carb do I need for my X Y Z racing Mar 10, 2015 · Mid size headers (do not know brand but probably about 1. If you try to use a carb with less CFM than required, performance and economy may be greatly reduced. My 74 C65 seems like a pooch with Holley on the 366. Thus, the basic size of carb for a 4-stroke 400 is a 40mm. The only challenge is that this process involves complex calculations. Find the right carburetor for your truck is a challenge but it is not impossible. A rough estimation is around 600-750 CFM for a typical V8 engine. May 16, 2013 · 1 have a 77 f150 with a a 466. a 600 Holley is adequate for the moment. To actually size a carb for an engine to optimize it you need a whole lot more info than we have been given and what information I have given on carb size is just from my own personal experience with small block chebbys. 80 cc = 18 mm Motorcycle Carburetor Jet Size Calculator. The question is, do we know the required cfm for our carburetor, and, if not, how to calculate the cfm of your Dec 16, 2008 · I have a 93 roller motor, that was switched to a carb setup. The advent of modern engines that make 400 hp or more has colored the reality of the past. 75" diameter) Turbo Walker dual exhaust ; 727 Torqueflight with shift kit ; We have the stock carburetor that we are saving for #s matching and we also have a Carter AFB Competition Series 9605s 3013 that is 600cfm. Sep 30, 2018 · I am gonna buy a new carb for my 440 4spd 67 GTX. Feb 3, 2002 · The 400 is a long stroke engine and remember the longer the stroke the faster the piston travels downward thus requireing a greater flow to fill the piston chamber irregardless of chamber size. 07@89mph 1/8mi. Dec 3, 2020 · Volumetric Efficiency: Most factory engines are a compromise between economy, efficiency, reliability, and performance; about 80% at redline. 030 Apr 17, 2020 · Choosing the right size carburetor for your engine can be tricky unless you know some basic math. So all of you guys think the 750 would be a good carb. Which is more important to you? An 800 DP would even work well too if you don't mind losing a little throttle response. Dec 23, 2014 · What size cam do you have? I gotta Racer Brown 540 lift & 292 duration (advertised, not at . A 750 would offer a bit more top side but the 204 / 214 cam is going to finish early and peak well below 5000 rpm. The size of your carburetor is determined by your engine displacement, driving habits and some aspects of your engine build. ) For the good of the Free World, DEMAND COMPENSATION FROM CHINA for their release of the Virus Originating in the Wuhan Laboratory. 7) + 1} = CFM required. Jun 14, 2017 · New to this forum. Carburetors (also known as "carburettor" in some countries, or simply "carb") are a smart device that create the correct mix of air-fuel in your engine. BACK FROM THE DEAD Pontiac V-8 400 CID Ram Air III approximately 85 percent. They both need to be dialed in and there is a noticeable difference stepping into the throttle if the carb is too big. My built is a BBC 427 . But if the 400 horses come from old fashion open chamber heads and big long duration cam then you'll need the tunability of a Holley with metering blocks on both ends whether it May 12, 2011 · i was looking at them they are somewhat cheeper, i see the 750 peformers are a 1407 , 1410 , and a 1411 so thats confuseing too, i used to have a 69 runner 383 auto 750 double pumper and had a big dead spot when you hamer on it till rpm's were there,i thought this was because of the bigger cam , may have been because it need wacume secondaries Oct 1, 2023 · How many CFM carb do I need? The CFM carburetor you need depends on your engine’s size, type, and power output. Dec 27, 2006 · Sometimes people fit a small carb to a large engine to get torque and economy which does work, but you must check the application the carb was designed for - a 302 uses smaller idle passages and acc circuit than a 460 so it's hard to make the same carb work down low on both when they may work fine at 1/2 or wot. Aug 10, 2023 · Carb Size: Why Do You Need For A Correct Carburetor Size & CFM Rating? A correct carburetor size and CFM rating are essential for your vehicle’s optimum performance. At the stripe look at the gauge if it reads more than 1-1. 451-500: 850-950. small-block Chevy. Mar 31, 2022 · 2. Other aspects to consider include; transmission type, maximum expected RPMs, exhaust system, and intake manifold type. Tags: Tech, Air and Fuel Delivery, Air and Fuel Delivery Carburetion. He said I need a 750 carburetor. Jul 12, 2004 · On a 400HP 460? - I need a carb. 5 times your engine’s displacement for optimal performance. I want to keep the stock look, the air cleaner & fuel line. Apr 7, 2015 · I believe a 600 or a 650 cfm would be a better choice, 85% of your driving will be in the lower rpm range, the smaller carb will give you more low end torque and better response, the 750 will give more on the upper end but not alot. Most 2-barrel V-8s and most USA-built 6-cylinders 75 percent. Aug 25, 2009 · Like the others have suggested a 750 is not a bad size for a nice street 350. Prices range from $270-500 plus. E- carbs are cheap and will just get you from point "A" to point "B" If it's running rich now it not because of the size it's because it is not set up correctly and the dist may need some curving. View attachment Jun 5, 2020 · It’s not easy to make 400 hp with a basic 350 Chevy using stock heads. I did try to do some searching but on a phone it isn't the friendliest. Carburetor sizing. This is its 19th year at the strip and I drive it there and home. 125 cc = 22 mm. Apr 13, 2013 · Remember that a bigger carb will hurt the off idle performance and eat more gas, but might give more high end. For example a 400 is going to make most of its power in the form of torque between 2,000 and 5,000 rpm. TECH TIP: Is my carb too big or small? Connect a vacuum gauge to a constant manifold vacuum source and attach it to the dash in plain view, make a pass. A general rule of thumb is to aim for a CFM rating around 1. 9 = 1354. 47@90mph 1/8mi 1991 Mustang LX 331 sbf 8. Once the 100 percent figure is obtained, the actual need may be obtained by multiplying the 100 percent figure by the appropriate percentage. A 750 vac. Feb 13, 2022 · A good dual-plane intake and a carburetor in the 650 cfm range (maybe bigger on a 400?) is a typical setup. The cylinder heads are where it may get a bit complex considering the cylinder head port and configurations vary. 500) & it runs good with a Edelbrock Performer 800cfm Carb. Do not over-esti-mate RPM column A. 115 stroke to get It is when you get into high RPM and greater displacement that you need a larger carburetor (more CFM). Very informative discussion about Holley-Edelbrock swap. Quick Fuel Specials. Pontiac V-8 400 standard 4-barrel engine approximately 80 percent. And then, at working pressure, free flow rating - as a rule of thumb - mostly is half of free flow rating. I assume they make an Edelbrock Performer intake for your engine, and it’s a frequent dual-plane budget choice. Jan 21, 2017 · I need advise to choose the right Carb. . Looking to get a electric choked carb but wanted to see what was a good combo for a good street and occasional quarter mile car. And it’s not getting enough gas in the engine. In our experience, you must have a decent set of cylinder heads in order to make 400 hp on a basic, low-compression 350 c. The catch with a carb that is too large is you can't really tell unless you swap in a smaller one and do back to back testing. Now I do run my engine to the redline and make people wonder what passed them, and I do tow, and my engine will turn upto 3000rpms on the highway and Jun 11, 2023 · Frequently Asked Questions Of What Size Carburetor Do I Need For A 454 What Is The Ideal Carburetor Size For A 454 Engine? For a street application, a carburetor with a 750-800 cfm should suffice. Trying to find the right size carburetor for your engine. 1. Oct 1, 2023 · Choosing the correct carburetor size for a 2-stroke engine depends on factors like engine displacement, tuning, and intended use. The amount of CFM required will determine carburetor size and quantity. I shift at 5100 rpm. Jul 26, 2006 · 396 carb size? Jump to Latest 1971 Chevelle Malibu 400 sbc 7. Two times 20 is 40. Do you think I just need to Apr 30, 2018 · To run around town and the occasional trip down the track a 600 CFM Vac secondary carb is all most of us will ever need. Its now in an 88 Mazda pickup, so the weight is a little over 3000 lbs with a C6 auto trans. Jul 5, 2012 · Do I choose the Holley Model 465 CFM 4 BBL Street Carburetor, for example, as per the online chart for tire size? Holley offers a next size 600 cfm carburetor, rated according to the Carter cfm/rpm chart, for 6,500 rpm. My opinion is to use at least a 750cfm carb, from the testing we've done on 400's in the 400-450hp range making peak power below about 5500rpm's, it is NOT too much carburetor. For example: a typical 355ci small-block—a 0. It depengs on what you mainly going to using the vehicle for. The motor has 10. AnywayI'm looking for a general carb recommendation for a new fresh build 396 bored . 36 rear gears. Nov 7, 2013 · A 400 needs a 750 CFM carb to properly perform. 250 cc = 32 mm. Jun 13, 2004 · 400 ci * 6500rpm * (1cf/(12*12*12ci))*0. What Size Carburetor Do I Need For A 350 - Final Thoughts. 390, 400, 400hp, 460 Jul 4, 2017 · I know, I know. fdej zvhccc jftsg rkhqxln alysclh swqgux nujrq bvcjt dmaouz sbij