Carb Recomendation: 850CFM Double Pumper

[torvald68]

There are alot of brands out there. Some look nicer than others. I have always used Holleys in the past. I need a 850cfm to support 650HP. I also want reliability. I see the BG Demon brand on Ebay for pretty reasonable price. Thanks for the input guys.

[68sixspeed]

I'm a big fan of keeping it simple, Holley HP series. I run a 750 reworked by VDL on the street most of the time and a 950 out of the box from holley for the track. The HP difference was around 12hp on it's best pull. The 750 actually feeds the motor fine and has better gas mileage, 'smells' better at idle (.700 lift at the valve and a lot of overlap on my motor).

I'm actually experimenting with the 950 on the street again and I'm having real good luck with it, just no power valve on the secondary makes it much more street friendly. I wouldn't hesitate jumping to the 950. For 650hp it's a better choice than 850's IMO. -Dan

[My427stang]

For a mail order carb, I like AEDs the best followed quite a bit farther behind by Quick Fuel.

The AED guys have been doing it a long time and will send a wet flow tested carb matched to your combination and driving style.

The next step UP from there is Bo Laws at BLP. Do a search online, he is one of the few real carb gurus left IMO.

I am a pretty sharp carb guy, I run a 1000 HP series on mine, and I am very disappointed by the Avenger and HP series today, especially the main circuit and transition effectiveness on the street.

My personal HP took a lot of time because it delivered very rich to cover up poor circuit response, and every one I have seen is the same way. The new main circuits just don't respond quick enough to pick up from the transition circuit, this causes a low speed buck and some odd fuel curves. WOT they run like a MOFO, but that's easy to tune throttle movement is a little harder

The poor setup on the new ones end up with a sledgehammer fix with guys using big shooters or severe bleed changes to make up for a poor main emulsion circuit.

Sorry for the soap box, but I think you'll be happy with AED, give them a call in Richmond, or BLP if you aren't afraid to spend even a bit more.

[Windycity1]

I run a HP 1000 done at Pro systems on the street with a 680hp 540 engine in my Impala. It runs good on the street.

[ponchopwr70]

I have a pro systems 950 on a 450hp 388 chevy and my car went a tenth faster compared to the 750 vac sec. carb I had reworked. I would try giving Pat a call at pro systems not much more than the holley hp950

[Blowngt92]

I am a huge fan of AED carbs now. After tons of research and calling the different manufacturers, AED was by far the most helpful. And the best part was that it was the owner of the company that assisted me! Decided to purchase their 750HO carb, and they said it would be perfect for my combo and I would have to do minimal tuning. Well it showed up and was about 28 degrees out. I bolted it on and was too anxious to wait for warmer weather and fired her up. Of course the carb has no choke, and I held it about 1300 for no more than 15 seconds and it idled perfectly and didn't need to adjust a thing but the idle down about 100 rpm. Absolutely amazing... Not to mention that there is no hesitation, stumbling, or burning your eyes with fuel.

[wmhjr]

Get one custom built for your specific application. There are some good people out there. I have experience with one who is absolutely excellent. Demonstrated proof of his carbs outperforming Demons and Holley units right out of the box. Very little tuning required. You pay a little more, but you get what you pay for.

[OLDFLM]

Another vote for Pro Systems

[wmhjr]

BTW, here is the email address for one vendor who will custom build you a tremendous carb. I can provide tons of examples of people having worked with him, and upon getting the hand built carb and replacing their Demon or whatever, picked up significant performance before a single tune. In order to really get the advantage, you need to know the specifics of your cam profile, head porting, chamber size, etc. He builds for daily drivers, street machines, all the way to full out race only applications. Though he prefers 4150 or 4500 configs, he'll also build a darned nice Q-Jet for those wanting to maintain "original" appearances with upgraded performance.

[email protected]

[OLDFLM]

Jeff built the custom 3310 for my old 400cid/400hp engine... you'd have thought I'd installed fuel injection!!! I couldn't have been happier with what he did to that old vac sec 750! I guess I didn't realize he also built high horsepower versions... looks as though you have a couple of great options to choose from!!

[wmhjr]

Yup, Jeff also builds some real high performance stuff. Mine has only been on a test stand and a dyno, but it's on a roughly 600hp motor and is real sweet. I've never heard of anyone getting a carb built by him that wasn't completely happy beyond expecations. I know he builds carbs for motors way beefier than my little 600hp poncho motor.

[Taman]

I run a quick Fuel P-850. This is the first carb that I have been able to have my TA idle at 950 rpm and drop into gear and idle at 850 rpm. Have a lot of friends that run the Quick Fuel and love them. I have run Holley HP950. Had a recall from the inside float bowls peeling.Holley replaced it and the next carb had secondaries that stuck open. No more holleys. They have a new type of carb but I'm sure about it. I have run a BG silver claw, which I liked but would not idle in gear. I have also run a Demon 850. Same problem and it also had chips from the machining. Don't know if BG got the quaility control issue resolved. Have heard great things about the Divincci and AED carbs. But remember that all carbs need to be tuned for your application. Wheteher it's done by the selling company or by you.

[Vegas69]

I hear nothing but good things about Pro Systems. I have a 850 AED ho and it has never run right. It's only problem is a tip in hesitation and I have ordered a another set of metering blocks. The part and full throttle performance is perfect. If I had it to do over again, I'd go with pro systems and have him spec a carb based on YOUR application specifically.

[BAD68GTO]

Biggs 950 carb here on my 467 NA, all roller, heavily ported Pontiac engine making 650 HP. He uses a modified Holley carb, looks terrific and he has provided me valuable technical support! Jessie is who I dealt with and I am a PICKY guy and was thrilled: http://www.bigsperformance.com/ and years later still answers questions with a smile-a RARE treat! Price was great too, a STRONG buy on my end and never a leak and SHOW quality! Gary

[Shaker455]

There are alot of brands out there. Some look nicer than others. I have always used Holleys in the past. I need a 850cfm to support 650HP. I also want reliability. I see the BG Demon brand on Ebay for pretty reasonable price. Thanks for the input guys.

I'd advise to stick with real Holley parts as they have the best engeering money invested.

Post your engine combo?

[BIGS]

Hello All & Happy New Year!!

There are allot of choices out there on carbs in todays world.....But in almost all cases when the carb is cheaper it has corners cut somewhere along the line......Like Shaker455 said, stay with the Holley design and Holley parts and have them set up to your specs....might cost a little more then the cheapo's on the market, but you will see the benifits in performance and quality.....Post your combo and we can help with the recomendation.....Jesse @ BIGS!!

[H2Ogbodies]

Agreed. I operate a small retail high performance store and do a lot of ther building/fabrication work inhouse and it's tuff trying to stay competitive with overseas/off-the-wall parts. I stick with Holley mainly because I want to support an American company first and foremost without sounding too political here....and that's not to say there aren't other US made guys out there...but Holley has a pretty expansive line of parts and has a pretty good reputation for quality. I'm also a avid historian and I respect the fact that the Holley name has been "doing it" since 1903.

[jch66]

i had a demon and it was nothing but problems, i got a pro systems carb now and i love it