I asked in another post about true cfm flow on large 4150 carbs and never got a really straight answer. Maybe if I explain my situation better, I can get the info that will help me make a decision on carburetion choices. I have a 528 Hemi, built for me by Dave Dudek that produced 712 hp on the dyno at Modern cylinder heads. We had some issues with the 800 cfm AFB's that were on the highly modified factory 2x4 intake. We switched to Daves 900+ cfm F.A.S.T carbs, and the HP jumped from 650 to 712. I sent my new 800's to Dale Cubic and he went thru them and said he could not really find anything wrong with them and he ran them singly on his test engine and called them good. I got them back and with a lot of testing with my Fast dual o2 sensor A/F finally got the jetting and metering rod combo right, it runs well, idles well, has acceptable cruise (13.8). I keep thinking of trying the Indy 4150 1x4 intake and was wondering how running a approx 1000+ cfm 4150 carb will work, performance wise, to running 1600cfm that I have or the 1800 cfm that we used on the dyno? I really am not interested in a Dominator as I don't really think they have improved them to where you would say that they are a GREAT street carb, but I try to be open minded. My car is 98% street and highway driven, so that is where I am coming from and looking for solid advice as I don't want to give up any horsepower for the simplicity of a single carb. Thanks, Lee.

Some of the benefits of a dual carb application is that there is one venturi feeding each intake port and each port runner is usually a lot straighter shot to the head than any given X style single four manifold. Depending on venturi bore and booster design & size, you might be able to squeeze some more flow out of a set of 4150's. The question is can your engine take advantage of it.

If you call 15+ mpg and winning Drag Week with a Dommy "not improved" I'm not sure what is but the RIGHT t-rams make great power and have nice distribution..........

For an engine like that I'd use two throttle bodies. Then you would have 2000 cfm of airflow if you need it, and you would have really nice street manners and good fuel economy. Look at the engine we just did for Hot Rod. It is similar to what you have.

http://www.hotrod.com/articles/dyno-tested-make-700-hp-trick-flows-new-fe-heads/

hi

why not try a holley 3 bbl .

950 or 1030 cfm .

mine is very street friendly !

If you have a running combo that you are happy with and making more than 650hp, in a 98% street driven vehicle, I'd just stay right there...

Thumper,I know you build a hell of a good carb, and I honestly just don't know that much about Dominators, BUT, My street car gets driven on Power Tours(2) Road trips to Woodward in Detroit (5) The last Woodward trip with the Hemi and a Mopar cross-ram with two 770 Holleys that still squeezed out 8 mpg at a 65 mph cruise cross-country. This is what I do with my car with nothing but a change of rear tires. Are you telling me a Dominator is a very good choice for that and if you are, could you please help me understand which type would work best? 2 circuit, 3 circuit, old/new.... Cause I would not know where to start.

Andy, when you first posted the results on the FE build, I posted that I would be looking forward to seeing info on setting up and tuning a dual throttle body FI, as yours is the first story I have seen on Duals.... lots of stories on singles out there, but my experience with setting up dual 4 barrels properly was a big learning experience over single quad and 6 packs that I am familiar with. I know you have a lot on your plate, but if you ever write an article on just what all is involved in tuning that set-up for max performance on the street, I will buy that book/magazine in a minute and I am sure many others would too!

Dave, your reply really puzzles me? I worked long and hard to get my dual quad setup right, it performs really well. There is always room for improvement, there is always something to be learned. If we all had the "Good Enough" attitude, we would all be driving our old Mopars around in mid 14 second trim. No Demons, Hellcats, Z06 vettes, who would have thought, 10 years ago, that we would see 9 and 10 second factory cars on the showroom floor? I guarantee you that our hobby was instrumental in driving this trend. The day I stop experimenting on my old Mopars will be the day they put me in the ground, I've been at it for over 45 years and I'm not done yet!

I have been running/bracket racing RB six pack cars for years. I can't tell you how many times at local Mopar events, a Hemi car would venture out on the track and make a pass blowing black over rich exhaust on the way to a underwhelming 15 second pass, it was embarrassing to see. I always said that if I ever got the money to build a Hemi, if it would not run at least mid 10's in street trim, I would sell it. I have not sold it. With Demons running 9's though, I would like to hold up for our side a bit better!
Lee.

The tuning is the easy part. Most people have trouble affording a dual quad EFI setup and/or installing it. The system just plugs together on a dyno but in a car it requires that a bunch of wires be run and the fuel system has be installed and then you need a O2 sensor in the head pipe and stuff like that.

Once it is installed the tuning is very logical. The easiest thing to do is to buy the complete system from Rich at Fast Man EFI and he'll include a base tune in with the box. His base tune should be close enough that the learn function would handle the final touches.

If you have worked thru a carb tune before then the EFI tune will be familiar, but easier. With a carb you have to guess how a change will get you close to the AFR you want. With EFI you select the AFR and the computer makes it happen.

Call me sometime cos it's easier than typing and more personal..........760-900-3895..........

w/r/t highly modified factory 2x4 intake: which one? What mods?

Don't rule out the Ray Barton single 4s. On my 540 inch hemi with Stage V heads, 13.5 compression I had a Stage V 2x4 intake with properly tuned 770 Holleys.
The Barton dominator intake with a 1200 CFM Pro Systems carb was worth 49RWHP!

Mercman, thats what I am looking for, real world experience with a similar combo. If you don't mind, tell me about your build.

Polyspheric, it uses a factory street hemi 2x4 intake that has basically been turned into a single plane. It flows close to the stage 5, this work was done by Dave and Modern Cylinder Heads.

I'll just assume, by the general lack of response, that one of two things is true:
1. I'm wrong because [insert famous name here] said so, or
2. everyone already knew that

Less work for me.

A friend put a Dominator on his Buick GSX clone. It idled well and made great power for a pump gas engine. He had Scotty McLendon do the carb.

http://www.amfibi.com/us/c/2915160-c781f367

99.9% of the time one won't notice 50hp in a 98% street driven vehicle. I doubt I would notice it in my 2,800# drag car. Might be worth a little on the time slip but assometer?

I have a new 572 C.I. pump gas street Hemi with a set of Stage V heads and intake with dual 1150 dry EFI throttle bodies that will have the Holley Dominator EFI system on it.
Rich at Fastman EFI will tune it for me soon, I'm waiting for the Stage V cast aluminum valve covers to get engraved and polish so I can finish the final assembly, plumbing and wiring on it before trying to dyno it.
I'll post the results on here when it is done This is for street driver E body 1970 Challenger show type car, not a fast street and strip car, dang it
This will be the first N/A EFI Hemi motor I've built and had tuned for straight pump gas, I'm hoping for 800 + HP at or below 7500 RPM

Lee 446, This motor at the time had stock Stage V heads that flowed 378 at 700. Cam is a bullet solid roller 730 lift duration is in the high 270 range (don't have specs handy).
3550 lbs 69 GTX that had run 9.71. Switching to Barton intake and 1200 CFM carb picked up 49RWHP and car went 9.49 @138.53. Im guessing that that is about 60-65 crankshaft horsepower gain.
Next gain was having Barton port heads. I flowed them before and after the port work on the same bench. Heads went 441 at 700.
Car went 9.21 @144
Easy to tune this set up. I will have to work on a off idle burble at around 1800 or so RPM, but idle and wot were almost spot on.

When I built the 540 for my Cuda, I knew based on my wedge experience that it would want a Dominator sized carb. I didn't want the additional complexity of duals and didn't want to spend the extra coin on an EFI system that would be obsolete (and maybe unsupported) in a few years (months?).

So the big question was which intake. I talked to quite a few people whom I felt knew what they were talking about. The big Barton was many guy's first choice for a single application.

At the Indy Cylinder Head show a couple of years ago, I stopped and talked to Ken about his recommendation. With my build info and a table full of different intakes, he recommended the Dominator flanged, dual plane.

I was skeptical. Enough so that I bought both a single and a dual plane intake and ran them back to back on the dyno.

The dual made over 30 lb more torque and only gave up 11 hp @ 6,800.

For my street car, that rocks. With that intake and ThumperDart's tune in the carb, the thing idles great and the throttle response is very crisp.

Dave Hall, you have contributed absolutely nothing to this post, in the spirit of your contributions, my advice to you is sell your race car and buy a Prius. That, and run a survey on Moparts about who can't feel 50 hp and who is willing to give it up cause Dave says you don't need it.
Polyspheric, I read the post before you deleted it!!??!! You brought up many good points, and one reason I have been thinking about going to a single 4 or trying out the new Edelbrock 2x4 is that, even with my limited knowledge of intake modifications, I know that distribution issues, puddling, etc, are almost assuredly occurring, it makes power at the top, but is not the best choice on a street car and yes, originally I had the manifold modded to keep everything appearing stock, just like you can't tell a 426 from a 528 on the outside. You can't take the old street racer out of me and stealth was the name of the game back in the day.

Merc, thanks for all the great info! I would be thrilled to have a 9 second street car, you are my hero! Very good facts, you have a bit bigger Roller than I do, heads flow almost identical, now ya got me thinking! Trouble is, my car with me in it is 4200 lb. race weight and I'm not taking the A/C or the PS out(69 Satellite)and my 225 lb could use a 20 lb. trimming!

Cab, As usual, I will be waiting eagerly to hear how your build comes out, you always make good and interesting contributions to help everybody out.

DaveRS23, I appreciate your input and real world experience, it is very helpful! I have looked at the indy and the Barton, not really a whole lot of choices for modern single 4 intakes for gen 2 Hemi's. You spent the money to find out what was best for you and you share this info to help everyone else out and I really appreciate it, gives me direction! Lee.

Dual throttle bodies on a Stage V intake would be the perfect combo for power plus drivability. But the Stage V intake has a different center to center spacing so you need to invest in a new air cleaner and all of the related stuff. It gets expensive and it takes time to round up all the bits and pieces.

On the 482 FE we used the Sportsman ECU which saved some money. I liked it but it didn't have a place to hook up oil pressure which kind of soured the deal for me. We could monitor a ton of parameters on the display but there was no way to see oil pressure. So in the car the guy will need an old style oil pressure gauge next to the LCD display that has all of the other info.

The nice thing with a setup like this is the ECU will keep a log for you so you can go look at how things are running. With a big investment in an engine like that it is nice to be able to keep tabs on it.