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I have a 68 camaro and i am trying to get some info on the air gap intake. The engine is a 350 with a mild cam. It has a holley domiantor single plane intake and a holley 780cfm carb. Would it be a good combo to put a air gap with a holley street avenger carb. if anyone has this comb or something else that would be better please share. I want to use the car for street/strip.

chris
 

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The standard RPM is still a great manifold and I keep hearing some people say that the Air-Gap is no better.....I dissagree because it has the potential to be a better manifold than that of a non-divorced type manifold. If you are looking to extract every HP and Ftlb of torque than I say run the RPM Air-Gap for it has benifits over the orginal RPM manifold.

You state 'mild' 350......what in your opinion is mild? I think the 780 is a little large for a 'mild' 350. What transmission do you run? Rear gearing? Do you have/want to run a vaccume secondary or a double pumper?

I have had excellent results with the RPM Air-Gap and the Holley HP series carbs. For a carb out of the box, it is a pleasure to use compared to some of the others. Even if you go with a 'Tuner' carb (ie BG, Carb Shop, Demon and others), you'll end up spending the same amount.

For a street/strip application, I would look for a carb that HAS SOME adjustability, the HP series or race Demon has just that (adjustable air bleeds, adjustable main circuits and so on). I would also look at running nothing bigger than a 750, but for a 'mild' set-up more like a 650 cfm.
 

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If it's a street driven car use the RPM. The 780 is a little big for what you have. Have you thought about a Q-jet there is no better street carb.
 

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I agree with Oger - no better street carb for the money than a Q-jet. Excellent throttle response, complete adjustability, demand operated, easy to work on and fuel efficient and inexpensive. Plus they're a fun carb to use and the stealth factor is quite high. A couple problems are that the Rochester decals are hard to come by and you'll probably never see them touted on HotRod TV.


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1967 Nova coupe daily driver
406, 10:1, 224° cam, Q-jet, 700R4, 3465# w/driver
11.75 @ 117 thru the mufflers
18 mpg on the road
 

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I dumped the GMPP 350HO in my 69 with the Performer Air-Gap (idle to 5500) and Holley 750cfm (#3310). To most this is seen as a "mild" set-up. I tried to match everthing up so that I would be able to take advantage of the power band of the motor. BTW, the "BC" rear in my ride is the factory 3.36 ratio peg leg. I am really, really happy with the AirGap and it looks cool too. The 750cfm in my opinion is not too much carb for a similar combo.

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1969, X-44, Export Model, Hugger Orange, Std. Int., BC Rear(soon to be a BT 12 bolt), PDB, GMPP 350HO, M22 Supercase, SSM Lift Bars, AirGap, Holley 750, FlowMaster American Thunder Exhaust, FlowTech Headers

[This message has been edited by Judd (edited 11-11-2002).]
 

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Well, yeah. Quadra bog technology is becomming outdated. Not to mention, if you really want tuneable performance you will spend the same amount of money on a 'Built' Q-Jet to an out-of-the-box HP Series, and that is where the difference is. From there the Holley still has the ability for further refinement and still more room to tune.

Why would you want to limit yourself?

Also, my recommendation for size was geared around a "Mild" set-up. If you plan on doing further modifications later, I myself would purchase a 750. I agree with JUDD, it is not too large of a carb, but if you were to stay on the mild side or didnt run your car that hard, a 650 would be an excellent choise.

[This message has been edited by chicane67 (edited 11-11-2002).]
 

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why dont you tell that to the super stock racers running 9's with "QuadraBogs", Holley has been around for just as long, are they outdated???

I'd agree that a HP series holley would be a better choice for a serious street/strip car, BUT "The engine is a 350 with a mild cam" Sounds like gas mileage might be a factor, and i dont really think he needs it.

The Q-jet would give you a good chance to hone your tuning skills, there are many many people out there who can really tune them.
 

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The carbs they run are not an out of the box carb....and I KNOW what is done to them and how much is spent on them to run 9's.

Yup Holley has been around for quite awhile, but all of the new or recent platforms are still based off of the Holley design....Demon etc. I know both the Holley and the Q-Jet are still in use today, but Holley has them hands down in shear numbers and in after market parts availability. The more owners, the more tuners.

You have also commented on gas mileage, hence my recommendation for a 650 not a 750 (not to mention throttle respone and so on). And with the available 'booster' technology today with the Holley, you can select more efficient boosters that you can change the BSFC by quite a-bit. This then allows a jet reduction of two to three and some instances five sizes in most applications. Efficiency has never been out of the question. My last mild small block averaged 26 miles a gallon.

I totally agree with the Q-Jet being an excellent platform for learning how to tune a carb, as it will take awhile just as a Holley.

[This message has been edited by chicane67 (edited 11-11-2002).]
 

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When I can get a Holley for $16 that runs as good as my Q-jet, I may become a Holley convert.

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1967 Nova coupe daily driver
406, 10:1, 224° cam, Q-jet, 700R4, 3465# w/driver
11.75 @ 117 thru the mufflers
18 mpg on the road
 

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Chicane, if you'd explain your point of view more in your original posts, it would better help out the forum. YOu have a good response the 2nd time, but didnt back up much in the 1st.
Cant argue that there are more parts available to the Holleys. A set up and well tuned holley is going to cost quite a bit (Check out what Pro Systems starts their prices at for 4150's).
Now If given the choice on an ALL OUT race car that sees minimal if any street use then the choice IMO would be a holley HP series or Pro Systems.

The point i was trying to make, which i think you got was that you can do alot with a Q-jet, if you know what your doing. Now to put this back in perspective we're picking out a carb and intake for a MILD street/strip (focuses on street) intake and carb combo.
Personally i dont think a Q-jet could be beat for that, they're inexpensive, and they are everywhere. They also get good mileage (especially for something rated at 750).
To put a HP series holley on a 13 second street car seems like Way overkill to me.
 

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If you look at my first post.....there are still no answers to the questions. You if want specific answers, we need to hear specific questions. My point of view would most likely envolve lengthy post replys. Let me put it another way. To correctly tune a Holley or a Q-Jet really takes about 80 hours of tuning. Think about how many hours on a keyboard.

Next, A set-up, well tuned Q-Jet will cost very similar to a HP series carb. As for the 'Pro Systems' products, why would I buy one of the priciest Holley Tuner carbs? Most of the mods that the 'Tuners' do is what you find on an out-of-the-box HP Series, with no added expense. All out race car or all out street car.... the carb has the same function. The more tuneable the fuel mixture, the cleaner, the more efficient and of course, the power produced. It doesnt mean that a carb that runs good on race car wont run as well on a street car. In fact, most street cars would greatly benifit from its use. All the money you spend getting it to where it can be and where you start from with a carb of this type, just saved you money right up front. Just think, put a 600/650cfm HP series carb on that 13 second car and tune it, it might just run in the 12's.

I see your point. Cost is a big deal. As the old guys taught me, "Do it right the first time or dont do it at all. If you dont have the money....save it up. Then get on with it. It's better to spend your money once, instead of too many times".

And to think, 68hotrod just wanted us to share our ideas. If he has the budget, allow him to spend his money as he feels fit. A $16 Q-Jet is just that....a $16 Q-Jet. I havent known one person/team that runs a $16 Q-Jet that didnt make more efficient power with that of a Holley.

Onovakind67, maybe if you took off the Q-Jet and learned to Tune a Holley like you have with a Q-Jet, you just might be a convert. I'll even give you a Holley.....

But then again what do I know? Its just a supported opinion.
 

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Don't confuse me with someone who hasn't ever used or tuned a Holley carb, or doesn't think that Holley is a fine carburetor. We run Holleys on our long distance road racing cars, and they work very well. We are restricted to 600 cfm on our 4-bbl motor and 500 cfm on our 2-bbl motor, so Holley is a very easy choice. The course of the 2000 mile race varies in altitude from sea level to over 8500' and temperatures from 40° to over 100° on the same day, so it's a carb tuners paradise. Tuning for a flat track and a 10-second long race is somewhat easier.
My $16 Q-jet is exactly that - a $7 carb with a $9 rebuild kit, plus about 8 hours doing a few modifications. Anything can cost a lot if you pay someone else to do it, even modifying a cheap old Q-jet. I think Val Hedworth gets around a Kbuck for his. Investing $600 in a Holley would really distort my $2000 motor budget, and leave me woefully short on my converter funds.
Another big advantage to Q-jets is that if you tinker with it and screw it up, you can get a replacement real cheap. Why limit yourself to just one carb, when you can have several?
What kind of Holley are you going to give me?




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1967 Nova coupe daily driver
406, 10:1, 224° cam, Q-jet, 700R4, 3465# w/driver
11.75 @ 117 thru the mufflers
18 mpg on the road
 

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I wish we were all that lucky with $16. I just never pay for something I can do myself, and the out-of-the-box HP is rightly suited.....

Ya see, I say I'll give you something and then you come out as a Holley user/lover. LOL !!

Ya blew it man !! It would of been a slightly hopped up 600 DP.
 

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Holley? What Holley? I think someone stole my password...
 

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I don't understand the argument of the Holley vs. Q-Jet...
- Both can be well tuned for performance
- Both can make great HP
- QJet is way cheaper
- Holley is easier to tune for high-fuel flow applications

What's the problem? Take the carb you like, tune it, and run it! Who cares if there are a limited few that run Qjets...the parts are still out there!

By the way, the Qjet is as fast as any Holley unless if you get below ~10 seconds. A Holley lover would say 'no way!' to that, but that's just because they don't know how to tune a Qjet! That's all!

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1969 Base Camaro
Vortec 355, Perf. RPM, Demon Carb., TH-400
All sheetmetal is NOS GM
See my webpage at: http://www.geocities.com/compuboy007/
 
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