Hi Mopartians,

What size blow through carb will I need for my new build 528 hemi?
I’m hoping to run two holset turbos into one carb on a MP 4bbl manifold.

Street use mainly and some strip, if it ever opens again...

Best wishes from John

Speak to these guys (y)

http://www.candsspecialties.com/store/html/blowthru.html

I would buy the biggest CFM Dominator type that I could
All Mopars need as much fuel and air than can get, especially with a Hemi and blower. to make as much power as they can

I'd have to disagree in this context. N/A or Roots for sure but an 850cfm blow thru would easily support 1500hp. A big cfm dom could be made to work but at low speed /low boost, my guess, it would be a turd.

The right foot controls how far the primary throttle blades open, correct
I have yet to see to big of a carb, including multiples carbs. hook up one to one on the linkage, be a turd down low if you tune the carb. or carbs properly
I've seen, heard of and drove cars that were toads due to poor tuning and improper parts selection because they made bad choices on mismatch parts.
BTW, have you driven, owned or help someone with a blow through street deal?
I have and ended up help make it a little bit better
As far as making 1500 HP with a 850 CFM carb on a blow though deal I would have to see that Probably not going to happen on anything streetable

I used a 600 Edelbrock on my 318, it made 520 hp&633ftlbs@4500. It was flowing 1024cfm. I used the smaller carb because it was a street driven truck and the 600 had better throttle response down low.

No disrespect intended here, I'm no expert for sure I'm an N/A guy who hasn't been hands on with anything like this, so I would take advice from guys who have way more experience, like C and S, CSU carbs, Pro charger, New Era.etc (Steve Morris made over 1500hp using a carb based on a 4150, 850cfm many years ago. https://csucarbs.com/shop/products/blow-through-850/ ). I am interested in this sort of thing so I will ask questions and have managed to pick up and retain a little info. So from what I've learned so far, the best advice I could give the OP is talk to someone who makes a living from doing this sort of stuff

I would highly recommend the Barton single plane intake for a 4150 carb with that type of blow thru. You will not see an intake that distributes fuel more evenly. As far as blow thru carb:

https://csucarbs.com/

http://www.apdracing.com/blow-thru-carb.html

https://www.prosystemsracing.com/blowthru/

http://candsspecialties.com/store/html/blowthru.html

Nice replies GUYS!

Prosystems seem to be doing the business for us Brits.

Non adjustment go anywhere carby, sounds 'too good to be true'...
I like the part about 'European expertise'...
Nice to get a mention from you GUYS lol...

But at a $1000 its right on the money and they have a great REPUTATION over here!

Have you heard of the old adage to never believe anything you hear and only half of what you see?
I don't believe anything the parts makers say to sell their products
I've built and dyno tested several types and brands of different motors with root type blowers with bigger carbs than 850 CFM for pump gas street use and retested them with more boost on race gas.
SB Chevy 356 C.I. with dual 625 Carter CFM blower carbs made 680HP on Oregon pump swill with 7.5 lbs. boost, 383 C.I. SB Chevy with better aluminum heads made a tad over 750 HP with 8.0 lbs. boost both with 6:71 blowers. 2nd blower motor I tested, a 454 C.I. BB Chevy with dual 600 Holley double pumper on a small bore 6.71 BDS blower and hydraulic lifter blower cam made 630 HP before tuning and parts changing, I change the cam and valve train and it ended making 800 HP with more boost(12.5 lbs.) that wasn't safe on the street so we lowered it back down 6.5 lbs. and it made right at 750 HP on CA pump swill with safe intake air temps
Two gen 2 426 hemi motors, one with a FAST EFI using a 3000 CFM Bug Catcher hat and the other had two dual Carb Shop custom built 1150 CFM Dominator blower carbs. The EFI motor ended up making 1300 HP at 7300 RPM after a lot of tuning and parts changing at 13.0 lbs, boost on race gas, it was a 499 C.I. all aluminum KB Street hemi block with ported Dart aluminum race water heads and a 10:71 Littlefield blower. The second blown Hemi motor was a iron Mopar Mega block bored to 4.250 after sonic testing it with a 4.250 stroke crank with s set of mildly ported Stage V street heads with the dual Carb Shop on top of a Littlefield 10:71 also, that motor made 927 HP at 7300 RPM on CA pump swill with 7.5 boost with 12% under driven with 33 degrees total timing, we reversed the pulleys so the motor had 13% over drive on the blower and put 112 octane race gas in it and retarded the timing to 25 degrees BTDC total and it made 1024 HP at 6500 RPM with 12.0 lbs. boost before it went into detonation We advance the timing to 27 degrees BTDC on the advice of the dyno operator and it went into detonation at 6200 RPM
Looking back we should have started at 20 BTDC with more boost but we didn't
I put the pulleys back to the under drive and advanced the timing back to 33 degrees and told the owner to please be really safe when driving that car, a 1971 Cuda with 17x29x15 M/T Sportmans bias tires on it, way nose heavy tire spinning monster
He had a 2001 ACR Viper that he drove on the street now and then so he had some seat time with a street car that had a little more than half the HP the blower hemi motor had
Boost is good, but they are not magic motors

As I'm sure you're aware, 850 cfm is the flow rate at a set pressure differential across the carb and normal air inlet density(The max it would flow on the inlet of any roots style blower like your examples). When you force air through a carb in a blow through system, it flows more air molecules since the pressure differential should be be higher and the density of the air is higher, especially if using an intercooler before the carb inlet. When modifying a carb for blow through, one of the significant mods is to increase the size of the needle and seat assembly to flow more fuel to keep up with the increased air flowing through the carb. BTW, I have run a blow through system, so I have some first-hand experience. I use EFI on my turbo engine now and would not use a carb again on a boosted engine. They work well, but EFI is better for a street/strip car IMO and I drive mine more on the street. That being said, the size of the carb that would be needed by the OP cannot be determined because a HP goal was not stated. A call to one of the previously mentioned carb vendors that specialize in this type of carb would be the best course of action.

had aCand S blow thru carb on my 610 cuin hemi with a f-2 procharger i messed with it for a couple of months i worked realy well on the street , never got it to work well on the track always had problems acually hurt the motor at ROADKILL on woodward ave . put a fast xfi on it with 160 lb injectors and it made 1381 hp and 1200 ftlbs at 6300 rpm on a engine dyno on the 1st pull, and was flawless in the car driving around i swear i get like12 miles to the gallon on e-85 , with efi you can change the tune in minutes with out opening the hood !!! i have 3 different tunes i can use 1 is a street tune for e-85 then a race tune for e-85 then i have a race tune for c-16 im a carb guy but EFI is the way to go on Forced induction FOR SURE

OMG, guys.

Real street cars with big hemi’s and 1000+HP WOW!

This is what I want to hear, real time experiences...
It’s not about going fast for me, just ‘bragging rights’ lol...

Yeh it’s got a hemi and TWO turbos...

They won’t dare say “is it fast and what does it do to the litre”...

Ps I don’t believe anything I see or hear, unless it’s on here or Nick’s Garage...



Pps, how did you get the motor to 610 cubes???

I use the FAST XFI system as well and honestly with all the features, controls and sensor feedback to data log for fine tuning, I don’t know why anyone would waste the time and money on a carb for forced induction. The EFI systems will self-tune to get you close on the tune, pretty quickly. You can fine tune it from there and be better-tuned than any carb, in all conditions. If you don’t’ know how to tune, there’s plenty of information to learn how or competent people to take it to. I know the initial cost is a concern for some, but if you’re messing with a forced induction Hemi, cost isn’t much of a concern, usually. By the time you buy the carb and all the separate feedback sensors & controls that you’d want for a forced induction engine (Wideband O2, data logger, boost controller for turbos, timing control to reduce timing under boost, ect.), it will cost about the same or more than just going with EFI, and you have a system that is inferior for fuel control and not integrated into one unit. Most people that start with blow through carbs eventually switch to EFI. You'll end up spending more time and money going that route IMO.

Omg blownDart,

You are wanting a dinosaur Moparman ( like me) to join the 21st Century with engine management...

Spent plenty of time with the guru that is Tom Nelson and his 2000 hp engines.
But they were not Mopar engines, so sad...

Yes I would love to pay an expert to build my 528 and dyno it at 1000+ hp,,,but...

It’s just down to finances and availability of parts here in the UK...

Many thanx for all the replies, they is Wonderful...

I recently put a Sniper 4500 on my Street/Strip 840hp Hemi and it has already made the street manners a lot better than the 1250 Dominator.

Guessing that’s your Cuda, Dracula?

Love the colour and the very tidy engine compartment.
So with 840 hp you won’t be needing any blowers lol...


We have a BIG car with loads of room in the front so we needed to fill it with TOYS.

What better than two turbos and an intercooler or two?

So now it gets tricky, engine management...

Blow through carb and endless tinkering or EFI...

I would go with EFI, and probably the Holley or Fuel Tech

I liked what this guy did with a blow thru carb and a Hemi.....Bout as fast as anyone I have ever seen with a blow thru deal...Watch all 5 days he was at Lights out 12 and even the build up to that....Lots to learn, if you want to be fast.

https://www.youtube.com/watch?v=DEVHZMWN9T4

https://www.youtube.com/channel/UCOwGSF5tgbzvCKj8seuUFRw

Use the proper size carb for the engine NA.

Your turbo engine does not use more air. It uses thicker air. Displacement is displacement. You are not changing that.


The air filter is your primary restriction. Everything after the compressor housing can be sized for a naturally aspirated engine. A monster carb will only make the engine a pig on the street. Response will be in the toilet.

Think about it. How big is each intake runner? How about each port in the head? If they move 350 cfm naturally aspirated then they will move 350 cfm under 847 psi of boost.

Air volume remains the same. Air density changes.

If the proper NA carb can keep up with the fuel flow then you're good. Most of the time that is not an issue.

I was making around 800 hp (657 at the wheel) with an Edelbrock 750 and an alcohol injector. Throttle size was not as issue.

For the record, I was much happier when I went EFI. Mine was an old outdated system with a custom built tunnel ram style intake and a forward facing 1700 cfm throttle body. Throttle response was soft but the power was better than the twin 57mm throttle body.

Talk to C&S carbs with a solinoid float and IMO a 1050 would be cfm to go with.