Carb size ?????

[Moose440]

Hey guys I would like your input. I have a .040 over 440 stock crank and rods forged pistons,stealth heads the motor has been decked and is 10.5.1 compression I have a comp 564 cam with 1.6 rockers 3/8 rods full msd and 3 inch exhaust. I drive on the street but it’s a street strip car. Currently it has dual eddy 600 mechanical secondary carbs with matching rpm intake. Im taking that off for a edelbrock torker 2. My question is what size carb do you guys recommend. I was going to get a Holley hp 950. But do you think I need bigger or smaller. And why. Thanks. Im going for most power and drivability.

 

[1STMP]

This may help;
There are calculators out there, but this is one
that shows the numbers.
https://toolsbible.com/how-to-calculate-carburetor-cfm/

 

[PRHeads]

If you’re talking Genuine Holley “950’s”, there are at least three different “sizes”.

Just look up the specs.

 

[slepr1]

This may help;
There are calculators out there, but this is one
that shows the numbers.
https://toolsbible.com/how-to-calculate-carburetor-cfm/

According to that calculator I only need a 600 cfm carb. And I have around + the same specs as the OP.

 

[496 polara]

I would want to know the trans/stall/and rear gears as well. That being said with enough converter and gear to stay in the powerband most would say an 850 double pumper.A holley 750HP mechanical secondary has served me well for years on several big block stroked or not.

 

[RJRENTON]

Would you consider a six barrel set up? Holley carbs are easy to tune and parts readily available. The 355 CFM center carb plus the two 500 CFM end carbs, opening on demand, may provide the flexibility you desire and allow for occasional strip exercises. Just my opinion of course.
BOB RENTON

 

[RemCharger]

I'd say go with the 950.
Quick fuel is my go to. They make an SQ950, which is a more budget street friendly version than the Q950

 

[33 IMP]

I have virtually the same setup in a street strip car. 3500 lbs 9"converter, 3.91s. A 440/.030 906s slightly worked, 727, 10 1/2, 557 purple, weiand team g, 3 1/2 flowmasters. I'm using an old (and I mean OLD) 4781 850 d.p. I have been seriously considering a new 850 race brawler, but I think they are backordered for a couple months.
I am probably gonna try my gold claw off my small block car. I thought it was set for 850 cfm, but I found out it was really 775. (Blue sleeves).
For yours? Kinda hard to go wrong with a 750-850 d.p., but like Dwayne said, check venturi and throttle plate size of any "950". Sometimes that number is marketing hype, the carb is really a 750. Nothing wrong with that,, just don't pay custom 950 prices for one.

 

[33 IMP]

According to that calculator I only need a 600 cfm carb. And I have around + the same specs as the OP.

Those cfm calculators for a race car are utter garbage. Fantasy Land.

 

[PRHeads]

The popular configurations for “950’s” are:

1.375 x 1.750(original HP 950)

1.450 x 1.750(Brawler/QFT 950)

1.563 x 1.750(Street HP 950)

1.600 x 1.750(XP 950)

 

[33 IMP]

The popular configurations for “950’s” are:

1.375 x 1.750(original HP 950)

1.450 x 1.750(Brawler/QFT 950)

1.563 x 1.750(Street HP 950)

1.600 x 1.750(XP 950)

So really the same as 750, 800, 850, and maybe 950 cfm?

 

[4mulas]

Edel avs2 800cfm would work nicely

 

[PRHeads]

So really the same as 750, 800, 850, and maybe 950 cfm?

I’m not sure if this is what you’re saying...... but.....

As far as the venturi/throttle bore sizing goes, only the “Street HP 950” is the same as an old school Holley DP.
The original style 850’s(4781)were also 1.563 x 1.750.

The flow rating for the original style Holley DP’s was pretty close.
650, 750, 850, etc.
The newer bodies with the contoured air entries........ not so much.

The first version “HP 750” and “HP 950” only flow about 30cfm apart(roughly 830 vs 860).
The main difference being the 1.687(750) vs 1.750(950) throttle bore sizing.

 

[RJRENTON]

How about an origional HOLLEY 3916-1 950 CFM 3 barrel carb? An oldie but goodie OR a later version rated at 1050 CFM. They're available on the internet. I guess it depends on one's point of view, vacuum secondaries or mechanical (aka double pumpers) which is best. IMO....let the engine decide when it can use more air flow.....I vote for the vacuum operated secondaries.
BOB RENTON

 

[1STMP]

According to that calculator I only need a 600 cfm carb. And I have around + the same specs as the OP.

I realize those calculators are all over the map,
and was merely trying to help the OP see where
CFM's are derived.
To get an accurate number, more info is
needed in his case.
For the engine I'm running:
CID x Max RPM ÷ 3456 = CFM
446 x 5800 ÷ 3456 = 748.5. (750 CFM)

 

[BSB67]

I’m not sure if this is what you’re saying...... but.....

As far as the venturi/throttle bore sizing goes, only the “Street HP 950” is the same as an old school Holley DP.
The original style 850’s(4781)were also 1.563 x 1.750.

The flow rating for the original style Holley DP’s was pretty close.
650, 750, 850, etc.
The newer bodies with the contoured air entries........ not so much.

The first version “HP 750” and “HP 950” only flow about 30cfm apart(roughly 830 vs 860).
The main difference being the 1.687(750) vs 1.750(950) throttle bore sizing.

A few different sources that I trust put the “original” 950 hp (1.375 Venturi) in the 840 to 850 cfm range. I tell people that my 950 hp drives like a 750, but makes power like an 850. I probably have 15 track pass tuning each, a 4781 and 950 hp. Could not get the 850 to et/mph as good as the 950. The 950 simply made more average hp with my setup

I think one of the two smaller venturi 950s would work well on the OPs car using a single plane intake

 

[1967coronet]

Somebody has to do it.......
thermoquad