[n20ta2]

I was looking at the Fst brand of carburetors as a buddy of mine runs a 950 fst 4150 of there's and loves it. I was thinking of running one of there 1050 cfm dominator carbs but after checking out there website it looks like they are releasing a 1050 4150 in March. I think of I'm not mistaken I can gain a small amount of hood clearance with the 4150 0ver the 4500. Being the same cfm would I lose much by way of hp choosing the 4150? They seem like decent carbs, cnc billet main body ect.

[johnta1]

Don't know anything about either of the carbs, but I'd check and see how they are rating the cfm of them as compared to Holley or most 4 bbls?

[n20ta2]

I will check that now thanks.

[n20ta2]

Can't find any info on there flow numbers. Might be better off just looking for a pro systems 1050 4150 or maybe a used dominator

[Mike Davis]

Not a fan of Pro Systems. Had out of the box Demons outrun custom built PS carbs. FST builds a good carb. Mark Whitener also builds some good race carbs.
How much power are you making?
If it's an all out race engine then a Dale Cubic or BLP would be a good choice.

[dragracerx2813]

Originally Posted by Mike Davis

Not a fan of Pro Systems. Had out of the box Demons outrun custom built PS carbs. FST builds a good carb. Mark Whitener also builds some good race carbs.
How much power are you making?
If it's an all out race engine then a Dale Cubic or BLP would be a good choice.

Mark Whitener does make some good carbs.

[n20ta2]

Should be around 700 hp. As cast high ports 11:01 461. 3.73 12 bolt, 295 60 et streets in 69 gto all steel.

[Dragncar]

Book has to make the best carb. Langer uses them and that usually means the best. But if a Cubic is over 2500$ those might be even more spend y.
Not sure how good the FST brand is but the prices are not bad.

[25stevem]

The Holley HP series have been darn good right out of the box also.

[n20ta2]

I don't have my intake yet, although I have a 4150 on order through kauffman. That can be changed to a 4500 as there still at least another 2-3 weeks out. I was thinking 4150 only because of hood clearance. So basically a 4150 1050 should theoretically flow the same as a 1050 4500?

[n20ta2]

If there both Holley's I should say

[PAUL K]

Originally Posted by Dragncar

Book has to make the best carb. Langer uses them and that usually means the best. .

Very simple logic. Reminds me of high school when kids would argue over which manufacturer makes the best stereo... I always thought if one company made "the best" all the other companies would eventually go out of business.

John Langer used to run a DaVinci carburetor and I think he may have won more Championships with that carburetor.... So would DaVinci be better than Book? SMH

[PAUL K]

Originally Posted by n20ta2

I don't have my intake yet, although I have a 4150 on order through kauffman. That can be changed to a 4500 as there still at least another 2-3 weeks out. I was thinking 4150 only because of hood clearance. So basically a 4150 1050 should theoretically flow the same as a 1050 4500?

Curious what type of 4500 does Kaufmann sell (sorry if it was mentioned above and I missed it)?

At 700 horsepower a true big carb 4150 will match a good 1050 4500. A twin blade 4150 style carburetor would probably be the fastest but not drive as nice on the street, as either of the other two carburetors if they were set up properly.

One other thing to consider is sometimes different manifolds will work better with a 4500 (regardless of air flow) because they with put the throttle bores closer to the intake ports.

[ponjohn]

Does a 1050cfm 4150 ACTUALLY flow 1050?

example - some 950's used 850 bodies.

[Sirrotica]

FWIW, Engine Masters just did a comparison on their dyno with a 950 cfm in dominator and conventional pattern. The results were the same for both configurations within 5 HP.

Freiburger wanted the dominator to win, just because he likes the look of the dominator so much better, but it as pretty much a draw no matter how they configured it. Two different manifolds and spacers/adapters on both manifolds. it was nearly identical HP, and torque.

[25stevem]

Dyno testing is by far not the final word unless you intend to never drive the car above 90 mph!

There’s no doubt that if your hood clearance is not optimal and your scoop makes for inlet air turbulence above 90 mph that the far bigger mouth of a Dominator deals with that better .

Buffering and turbulence makes any Carb appear smaller then it is, not to also mention how such buffeting makes for fuel distribution issues and the added power loss and or engine damage that can stem from that.

The ideal hood scope is one that is open to the rear , is angled like the windshield, and sit’s no more then 2” away from the windshield..
This set up pressurizes the mouth of the carb with no buffeting taking place.

Of course this ideal set up can only be had with a lift off hood.

[Steve C.]

To mirror the above information...

Tid bit from a magazine that might be of interest.

When designing a cold-air package, remember that an optimum entry will provide a nonturbulent air supply above atmospheric pressure. Front-facing hoodscoops typically begin supplying air at lower speeds, while rear-facing scoops supply air at higher speeds with less turbulence. Inside the scoop, all air ducts should be designed so that air entering the carbuertor will do so smoothly- preferably through a air cleaner or other diffusing device. Be sure that the bottom of the air cleaner's lid does not rest too closely to the top of the carbuertor where it will restrict air flow. You should leave at least 2 inches of clearance.
If your building your own scoop, make sure the incoming-air opening is at least 10-15 percent larger than the carburetor venturi size. This typically equates to about a 20- to 25-square-inch opening in the scoop. For optimal performance, the roof of the scoop should be placed about 2 inches above the carburetor. Be careful not to build the scoop too high because additional clearance can sometimes create turbulence. Adding a scoop to the carburetor system can also effect the air/fuel ratio of the existing combination because the incoming air will hold more oxygen molecules. As a general rule, you might want to begin your tuning by jetting up about two jet sizes (from prior optimum jetting) after you've added a cold-air package.

On another note.... and take this one with a grain of salt !

Very successful Pontiac Super Stock racer John Clegg stated that a front-facing hood scoop will work as a ram air source only if the car in question is doing 200 mph. Through on-track testing with a computer, he found that the 'wrong-facing' scoop worked better than when it was mounted facing forward.

He used a small Harwood scoop mounted backwards on the hood of his 8-second former record holding Firebird ( it looked like a large size Trans Am scoop ).


.

[n20ta2]

The intake will be a kauffman northwind port matched to the heads. This is going under a stock height steel 69 gto hood. Scoops are cut out. Was going to try and get a drop base air cleaner to fit hopefully. I'm still worried about clearance but kauffman did say it would fit.

[Sirrotica]

They (Engine Masters), said, if the car was only for competition, the dominator would be better suited, but for street driving, the conventional pattern was much better for drivability on a dual purpose car. I'm just relaying their information given on the show, I have no dog in the hunt.

I only use a Q Jet for my own cars. I never liked holleys for a street car, or on my dirt track cars, and autocross cars either. I wouldn't ever use either of the holley carbs on my own personal vehicles. I had the competition tell me that my car would run much better with a holley, until they came in behind me in a race, priceless........

A Pontiac, with a Q Jet, and dual radiators, with a turbo 400. A total departure from a typical dirt car. A typical dirt car consists of, SBC, holley carb, single radiator, usually a 3 speed stick, think outside the box, and not follow the leader. Proof is in the winners circle.

There are more forms of racing, than just drag racing, you'd never know it from reading this forum though.

[Skip Fix]

4150 HP series are rated cfm at a different pressure than the old 4150s-why a 1000HP has the same throttle plate and venturi size as an 850 DP. I think the Dominators were also rated at the same pressure as the old Holleys-so a current 1050 4150(unless a Demon with removable sleeves and the largest venturis) and a Dominator 1050 will not flow the same.

I think some of the HP series have a dual bolt pattern baseplate and Brasewell also makes a 4500 pattern 4150 body baseplate . I swapped one of those on an older HP 1000 for a buddy to use on an SD modifed Holley intake that had a Dominator pattern. Out of the box HP 1000 picked his cars 60 ft and drive ability up over the 8896 Dominator on it. 10.50s 63 Tempest