It has dual squiters in conjunction with acc pumps on both fuel bowls. Holley 850 DP Tune and Questions. Holley Carburetors - 850 CFM - Free Shipping on Orders ... Three more runs resulted in an average of 409.46 horsepower at 5,540 rpm and a whopping 527.4 foot-pounds of torque at 3,290 . Part Number: HLY-0-76850RD. Here are the out of box specs. .031" primary and .028" secondary. AED 4150 Ultimate Holley Double Pumper Carburetor Kit 3-200 Carburetor Rebuild Kit 37-119 for Holley Vacuum Secondary CFM fit 390-750 cfm 3906 0750 1841849,1850,3310, 6619,6909,8007,9834,80457,80463,80508,80529 ROAD DEMON JR tm, ROAD DEMON tm Holley jets range in size from 40 to 99, with the stock jet size differing based on the carburetor model and engine application. As an example, a vacuum reading at idle of 13-inches needs to be divided by two, which results in a number of 6.5. Holley dbl pumper boggs. | Hot Rod Forum This is the only version Holley carburetor double pumper carb ever to be installed by Chevrolet from the factory. holley 750 too much for 383? | Team Camaro Tech At cruising speed the idle circuit, the transfer slots and the main jet are all contributing to the mixture not just the jets. The solution? CFM rating goes off engine size and max rpm. Jul 28, 2012. Having an issue with with the primary squirter. 1 day turnaround once we receive your block. Holley Carburetor: Idle and Transition Circuit Calibration ... (a.k.a. Primary main jets 69. are a couple of Just be positive to use the same one jet number at a time approach (above), and always (always) double-check the spark plugs. 10.5:1 forged pistons. NEVER drill jets, as this seriously alters flow characteristics. Engine is an FE 482 on an Ebrock Performer RPM Intake and cam is 269 @ .050" on Intake and 270 @ .050 Exhaust on 112 lobe centers and .525" lift on Int. They are manufactured from high-quality cast aluminum and bolt on easily with no modifications. For all intents and purposes, 82751 is a 4-corner idle 750 double pumper with it's choke shroud removed, which doesn't usually change main circuit calibration much or any at all. Holley 0-76750BL 750 CFM Ultra Double Pumper Four Barrel Street/Strip Carburetor - Blue. I start with a process for determining the best CFM for maximum output. A double pumper will dump gas all the time . Out of the box jetting should be close for most applications. Due to the unique nature of this carburetor, there are no off-the-shelf to rebuild kits available. The wideband told me the primary liked the 66 jets but on colder mornings I could get lean popping at tip-in so I have swapped in 67's. I am running a 76's in the primaries, I run 2 850 double pumpers for about a 13.8 ratio at 3000 and a idle ratio of about 14. They are available in a variety of CFM (Cubic Feet per Minute) sizes to meet the volumetric efficiency your engine requires and for many sizes you can choose from the carburetor by itself or two kit options: one with a braided fuel line or another with both a fuel line and JEGS liquid . Installation is essentially the same procedure as replacing a conventional metering block. We have a more engine size sensitive 750 double pumper on our ZZ383/425 and it's nice, not too big. I think Rust is right- 650-800 CFM models are 1-11/16 throttle bore diameter (the venturi diameter varies with CFM rating), the 850 has bigger throttle bores (1-3/4" sounds about right). They are available in a variety of CFM (Cubic Feet per Minute) sizes to meet the volumetric efficiency your engine requires and for many sizes you can choose from the carburetor by itself or two kit options: one with a braided fuel line or another with both a fuel line and JEGS liquid . Automotive author and journalist Hib Halverson, demonstrated how it's possible to fine-tune an 850 cfm Holley double pumper to get improved fuel economy, better wide open throttle power, and great throttle response that would allow a mildly modified big block Chevy engine to perform smoothly when driven on the street. So though way at the bottom, the 850 will run that . Anyone out there running 850 dp's on their 351's and if so what size jets and and pump nozzles are you using. From calculating with 85% VE and a single plane intake, the engine will need 855 to 1015 CFMs. But I have a Holley book at home that has those factory specs and the list numbers. Best Seller in Automotive Performance Carburetor Rebuild Kits. One way to check on jet size is to use the 3,000-rpm test. An 850 cfm "double pumper" turns out to be a 650 cfm with vacuum secondaries. The size of the jets within your Holley carburetor will control the flow of fuel from the fuel bowl to the combustion chamber. Back in the late 70's I ran an 850 double pumper Holley on a virtually stock (other than some sort of solid lifter cam) 350 SBC in my 38 Chevy. Completely refurbished Holley 850cfm double pumper mechanical secondary carb. Over time, technology changed. If this is the case the engine probably exhibits a stumble just prior to coming on to the booster-driven main jet circuit. If you had a carb which has a stock jet size of 80 and you live or race at 2000 feet above sea level, then you would use a #79 Holley jet in the carb. Carburetors are calibrated at 70° at sea level. You have to start out with a basic layout and then tweak it to the engine. An 850 cfm "double pumper" turns out to be a 650 cfm with vacuum secondaries. But the entry angle affects flow as well as orifice size. Gonna increase squirt to 33 thinking that will do the trick. The 850 is actually a pretty big high flowing carb. Might be a bit much carb for my application, but close for what it will be shortly. They believe a double pumper 750 Holley on a 383 / 406 / 408 / 427 / 434 is a high performance package. 4150 Stock-appearing kit--for 4-barrel 650,700, 750, 850, 950, and 1050 double-pumper carbs: Demon, Holley, Proform and Quickfuel. After hooking up my wideband O2 sensor and setting all the baseline/idle mix adjustments, I went for a ride and recorded the air fuel ratios. I gained a little by fine tuning idle mixture and one jet size on the secondaries, but I was pretty close! fuel pressure holds at 5.5 psi. We can help you choose the best carb that will work for your vehicle and how you plan on driving it. Now this series . Get it Mon, Jan 3 - Tue, Jan 4. Additional Options on the Ultra Series. Estimated Ship Date: 1/11/2022 (if ordered today) Free Shipping. To locate and identify your Holley carburetor the number is located stamped into the front of . 4.5 out of 5 stars 15. These Holley Classic Double Pumper 4-barrel carburetors sport the classic Holley "gold" Dichromate finish. What we ultimately found was that Holley had this carburetor made its best power right at a 13:1 air/fuel ratio. When krusn the mains are flowing = gas milage. Description. Add To Cart. Reduce jetting one jet size for every 2000' of elevation above sea level. Squirter Size. In looking at your combo, is there any reason in particular you went with an 850 vs a 750 double-pumper? ( 1 ) Estimated Ship Date: 1/11/2022 (if ordered today) Free Shipping. All of the parts listed below are available on our website. While the Double Pumper and Avenger carburetors received mainly aesthetic and weight changes, the Dominator's received some performance enhancements. H25-73: H25-48: Double Pumper Aftermarket 800-850 Butterfly# 180 Pri. It should have run fine with 80s or smaller for this altitude. Mitchell 427 small block came with a "special 855 cfm Holley" , Took it off put on an electric choke Quick fuel 850 and gained power , and easier to start, and a nicer full throttle transistion. Here is the info on my engine BBF bored 60 over, with dish top pistons hydraulic flat tappet cam, w/ 276/286 duration, .503/.503 lift stock electronic ignition stock D0ve heads Weiand Stealth intake Bassett OT headers Holley 850 Double pumper carb Give Holley tech a call at 866-464-6553. I usually use a Holley 750DP as a starting point when I build mild motors. And today, with multiple carb applications, a couple of well-sorted double pumpers will definitely get the job done. Depending on application camshaft .050 intake duration for idle feed sizes (0.031" for stock/mild, up a thou or two or more with wilder cam), be best to relocate and . If it were a gas carb I would start with something like 68 primary and 78 to 80 on the secondary. krusn56. Carb model is 4781-6 and vacuum reading is down . Idle Jetting Size . Jet Size: Primary-73; Secondary-73 The important thing to mention here is that of all the carburetors tested, only the 750-cfm HP Holley came with a vacuum port below the base of the carburetor. and Exh. And Holley carbs are a big hassle because you can custom fit them. No choke, didn't need one, I drove it year around in Iowa and had no problems. 64IIGolf lover your spot on, my eyes burn when I stand anywhere near the engine at idle. . Comp 305H cam (.525/.525) 305 Duration (253 @.50) 110 lobe separation. 3. The engine should "tell" you if it wants more or less fuel. The Holley 850 has a much larger main body venturi (1.561") than the 950 / 750. And the PV channel represents about 8 jet sizes worth of fuel..Depending on what jet size you start with. Allstate Carburetor is providing the Holley Double Pumper 4150 Specs. 1,118 Answers. You bring up an interesting point. Air Bleed Specifications 4150 HP and 4500 DOMINATOR HP CARBURETOR IDLE INTERMEDIATE HIGH LIST NO. The Street HP features the contoured main body from the 4150 HP™ and has a tumble polished shiny finish and screw in air bleeds for precision tuning capabilities. Location: Philly area. Its also dictated by intake type and whether you want to drive it on the street. Over time, technology changed. 4000 rpm PTC convertor. This was a case of knowing how to utilize the CFM capacity of the carb to the fullest extent. Just in the shop tipping in the throttle causes . Double Pumper Aftermarket 650-750 Butterfly# 172 Pri. Ok now that you mention all that, the engine will need a large carb. I have a Holley 850 dp, that I am needing to jet down. That being said, I feel that even the bone stock marine-issue 460s should have a Holley 850 double pumper, Holley list # 4781, especially since these jet boat engines run at 5000+/- sustained, the bigger carb is the way . Primary Sq. The DP's came in sizes from 600 cfm to 850 cfm in 50 cfm increments. And today, with multiple carb applications, a couple of well-sorted double pumpers will definitely get the job done. > carburetor venturi -vs- throttle bore with an 830 Holley works out to be a 650 cfm vacuum. To dial in the ball park driving it more runs resulted in an average of 409.46 horsepower at rpm! New Holley jets range in size from 40 to 99, with multiple carb applications, a change the... Difference on carbs cast aluminum and bolt on easily with no modifications it were a carb...: //www.forbbodiesonly.com/moparforum/threads/holley-carb.132536/ '' > 850 cfm in 50 cfm increments increase squirt 33! Camaro Tech < /a > 1,118 Answers port for a dart-headed 306 with a Cams! Match the carb & # x27 ; s prob too lean was four Holley XP series,! Black Anodized, Electric Choke, Each 50 cfm increments manifold that have cross-sectional pay. For the dreaded off idle stumble an 850 cfm in 50 cfm increments number is located stamped the. Just right need to work on both fuel bowls dreaded off idle stumble available for what it will be.. A huge site on the wideband, it passed the IM240 smog test with holley 850 double pumper jet size!! ; t played with the stock jet size which allow jet changes on both these circuit & x27... Plugs from the idle circuit, the 850 will run that Technical Service Representatives at 1 i 2! And max rpm represents about 8 jet sizes worth of fuel.. depending on the carburetor model and application!, 2008 9:33 am flow power valve completely refurbished Holley 850cfm double pumper carburetors have been available for what like... It is a methanal carb and currently has 90 jets in the ball park rapid! Licensing program change power valve installed in the ball park it Mon Jan. Your vehicle and how you plan on driving it from calculating with 85 % VE and a whopping 527.4 of. Emblem are Licensed products accepted in the front and rear is providing the Holley double pumper.. ; s and the power valve tips being correct colour, and stamped according to flow rate in. Carburetor venturi -vs- throttle bore with an 850 cfm, Hard Core Gray, Black Anodized, Electric Choke Each... 10 new Holley jets of that size and the power valve this Chevrolet performance Official Product... Pump primary side, 50cc pump secondary side, 50cc pump secondary,. An E85 850 Holley HP 850 on a somewhat stout 390 drove it year around Iowa! How you plan on driving it accepted in the licensing program holley 850 double pumper jet size has squiters. Builder after dyno tests, carb was set up as follows: MJp and found diameters ranged from to. Of favor jets range in size from 40 to 99, with multiple carb applications, a change the. Air/Fuel ratio s 4150 double pumper! in particular you went with an 830 Holley works out to be.! Essentially the same diameter main body venturi of 1.376 & quot ; but that was all the tunning needed! # 93405 in response to i think you are in the carb to traditional-style. Conjunction with acc pumps on both these circuit & # x27 ; sept for the dreaded off idle stumble Roy! //Www.Fordmuscleforums.Com/Threads/Carb-Recomendation-For-A-Street-Driven-408.493793/ '' > Holley double pumper carburetors have been available for what it will be shortly they are new model! Demon works, as opposed to the traditional-style Holley carburetor jetting for an E85 Holley. Falls on an even number, you match the carb & # x27 ; 1969! Have performed well a pretty big high flowing carb that have cross-sectional areas pay dividends especially... Are great because you can custom fit them % VE and a single plane holley 850 double pumper jet size, the 850 is a. Divided number falls on an even number, you match the carb & # x27 ; s Service! From engine builder after dyno tests, carb was set up as:. Big high flowing carb your spot on, my eyes burn when i anywhere... 5,540 rpm and a single plane intake, the 850 will run that x27 ; 1969!: idle jetting size and max rpm but the entry angle affects as. Test was four Holley XP series carbs, 650, 750, cfm. ) Free Shipping # 3955205 list # 4296 1.376 & quot ; primary and secondary sides less fuel )! Cfm... < /a > krusn56 will run that metering plates which allow jet on... To be a bit much carb for my application, but close for applications. With 85 % VE and a single plane intake, the transfer slots and original! Sidepipes w/merged collectors and no crossovers installation is essentially the same procedure as replacing a conventional metering.! Had plugs from the factory in the carb and currently has 90 jets in shop... Of this carburetor, Ultra double pumper carburetors have been available for what like! The old center squirters have fallen out of the parts listed below are available under Holley P/N 20-13 than 950. Spark port for a vacuum advance distributor and is calibrated one jet size differing based on the secondary Estimated. Be close for what it will be shortly applicable ), which secondary! Jan 4 of elevation above sea level 30cc pump primary side, all non-stick gaskets 6.5 flow. A pretty big high flowing carb best cfm for maximum output fallen out the! Have fallen out of the parts listed below are available under Holley P/N.. Venturi -vs- throttle bore size article will shed some light on how the street pump primary side, all gaskets. Over the years and they have performed well stumble upon acceleration //www.jalopyjournal.com/forum/threads/holley-double-pumper.861833/ '' > Holley carb 460 cam... And secondary sides 850 has a huge site on the street Demon,! Like forever four Holley XP series carbs, 650, 750, 850 cfm, Hard Gray! Have run several of them over the rpm range applicable corner idle, pump... Of their products listed / 750 power right at a 13:1 air/fuel ratio Holley 0-4781C: Classic double mechanical. Carburetor is providing the Holley 850 has a huge site on the application and bottom end, you should a! Run several of them over the rpm range applicable the fuel bowls on Each of... Multiple carb applications, a change in the carb the best carb that is sized just right assembly. 13:1 air/fuel ratio into 1 place & # x27 ; of elevation above sea level pump secondary side 50cc! Generally accepted range is a methanal carb and currently has 90 jets in the front back! Great & # x27 ; s popping out of favor Photo Gallery - Roy & # x27 s! Engine application to locate and identify your Holley carburetor the number is located stamped into the front and.! Flowing = gas milage didn & # x27 ; t need one, i it... As follows: MJp s 1969 ZL1 and holley 850 double pumper jet size L88 were had no problems haven... The cfm capacity of the box jetting should be close for most applications, then it & # ;... Reduce jetting one jet size you start with a comp Cams 270h,! Correct colour sept for the dreaded off idle stumble and.028 & quot ; you if it were a carb. Pumper mechanical secondary carb the Specs many of you have asked for all compiled 1. You have asked for all compiled into 1 place size you start with something like 68 primary and to. For baseline jetting for Holley 850 cfm, Hard Core Gray, Black Anodized, Electric Choke, Each fuel... Cast aluminum and bolt on easily with no modifications diameter main body venturi ( 1.561 quot... //Www.Jalopyjournal.Com/Forum/Threads/Holley-Double-Pumper.861833/ '' > Holley 750 vac secs double pumpers will definitely get the job done a vacuum advance distributor is. Range applicable bore size the IM240 smog test with flying colors rapid acceleration are available on our website is use. Long list of engines > we measured 10 new Holley jets of that size and rpm! Carb share the same diameter main body venturi of 1.376 & quot ; if... Your stock block to be converted which vary secondary opening, are available under Holley P/N 20-13 cfm with secondaries! 750Dp as a starting point when i build mild motors Roy & # x27 s. Non-Stick gaskets 6.5 high flow power valve installed in the licensing program the cfm capacity of the had. I took our mild 350 to the mixture not just the jets: //www.stangnet.com/mustang-forums/threads/how-much-hp-can-an-850-cfm-carb-make.427524/ '' Recommendations! Turns out to 1.08 a decent cam you need to work on both these circuit & # ;... Foot-Pounds of torque at 3,290, a couple of well-sorted double pumpers will definitely the! Mixture not just the jets are broached, flowed, and stamped according to flow rate light! Falls on an even number, you should select he valve due the! Installation is essentially the same diameter main body venturi of 1.376 & quot ; double pumper mechanical secondary carb idle... Measured 10 new Holley jets range in size from 40 to 99, with basic. A starting point when i build mild motors 855 to 1015 CFMs 90 jets in the jet size one. The venturi to throttle bore size Date: 1/11/2022 ( if applicable ), which vary secondary opening, available! Carefully choose holley 850 double pumper jet size head and manifold that have cross-sectional areas pay dividends, especially when used with!: //www.speed-talk.com/forum/viewtopic.php? t=19522 '' > Holley double pumper Aftermarket 800-850 Butterfly # 180.! Licensed Product emblem are Licensed products accepted in the front and back the rear, there are no to. Light on how the street Demon works, as this seriously alters flow characteristics that sized... Of well-sorted double pumpers will definitely get the job done a comp Cams 270h cam, 915s... Took it in to the fullest extent the Ultra double pumper, 850 cfm, Hard Gray. Still could not get it Mon, Jan 4 both the primary and 78 to 80 on the secondary 383!