hi , i have a mild 350 in my 1985 camaro ,,with edelbrock rpm intake with a hot cam and headers etc..right now i have a 700 holley double pumper ..i hate this carb because it guzzles gas like crazy and it stinks of gas all the time and i have to adjust it constantly...it takes off like crazy when i crush the pedal ,,but i can see the gas gauge go down!!..i have the chance to get a edelbrock 1405 600 cfm carb ,,,would this give me a good performance/economy option?

 

Not like the original qjet would.

 

mooch1, welcome aboard thirdgen.org.

I moved your question to its own thread because it didn't really relate to the topic of the thread where you posted it. We prefer threads to be single topic.

I agree with naf. To expound, tune your Holley. If it "guzzles gas like crazy", you've got a tuning problem.

Let's start with the basics: What distributor are you using? Is the tune-up fresh? Where is the timing set? Is the vacuum advance working? Have you adjusted the float level or rejetted the carb? Where's your fuel pressure (what are you using for a fuel delivery system)?

Having said all that, if you don't want to go through the tuning basics of the Holley, put a q-jet on. Nothing else makes any sense.

It would also be helpful knowing more details - what you mean by "mild 350", transmission, rear end gearing, exhaust, use of the car, etc.

 

hi thankyou , well the engine has new cap and rotor and plugs a new fuel filtre..it is a 350 V-8 with presently the holley 750 double pumper and it has an edelbrock rpm intake ,,hot cam(forget the specs) headers with 3inch exhaust all the way to the back with no cat or egr valve ,,no antipollution... regular GM distributor...it's got a 700r4 with a corvette servo and shift kit...rear gears are 3-23 with an auburn posi....i have hated this holley since it came with this car,,,,i can get a edelbrock 1405 600 cfm carb ...it's new ...why woudn't it be better ?....it looks very simple to rebuild if i had to one day , besides it would save some gas , but i guess i would lose some power... i don't really race this car , it goes trust me!! , but i like the highway better--weekend car....what do you guys think?

 

i personally like the edelbrock carbs, because they are a good design. But they don't get much love here, cause most people are riding the nuts of holley and the allmighty qjet. there is nothing wrong with the edelbrock, and it's probably better sized to your engine.

 

thanks, i think so too...i have heard a lot of good things about these carbs.,,but everyone says holley is the best...i think holley carbs are good but require constant adjusting or rebuilds...the Q-jet for me is the best carb ever made ..you can upgrade the jets and it will be the best carb out there...i will try this edelbrock 1405 and see how it does on my car..thanks.

 

Holleys don't require constant adjusting or rebuilds. If that's what you're doing, you're doing something wrong.

The Edelbrock design is old. It works, but the secondary design in particular is lacking. The Performer secondary opening isn't adjustable, and the AVS series is only slightly better. It doesn't hold anything over a q-jet in that regard.

If you don't have any carb or distributor, and are willing to settle for the cheapest thing to put on, go ahead and get an Edelbrock. If performance is your primary goal, you'll be getting a Holley. If fuel economy is your primary goal, you'll be getting a q-jet.

If you have a functioning q-jet or Holley, it doesn't make a lick of sense to spend money on a Performer.

 

For cheap you can't beat a $30-50 used qjet and $30-50 in a rebuild kit and cleaner. If you get a used one from another vehicle with the 700R4 it should come with the correct TV bracket for the tranny cable.

'Course your manifold is likely a square bore and you'll need a spreadbore adapter to bolt on a qjet, that's another $10-15 and you may run into a hood clearance issue. But, hey, you'll need the same adapter for the Edelbrock.

 

hey guys , this why i joined this site ..very helpful!!,,but i will keep my holley double pumper just in case ,,i have my 1405 edelbrock carb ,,i will install it and see what i might lose in performance and see what i would gain in fuel economy...again , edelbrocks are getting bashed,,,i have a good freind and he says the q-jets are worth keeping,,,,but holleys are good but not always cooperative,,,i will let you know how it runs...thanks and if you have other suggestions --go ahead.....

 

hi , i had another question , do i need to lower the fuel pressure to my 1405 edelbrock, i have the stock fuel pump and it may produce way more than the 6psi that edelbrocks can handle....either i change the fuel pump to a lower psi one or get a fuel pressure regulator?...does this make any sense?

 

The easiest way is to install a 3 port fuel pressure regulator, like the Mallory 4309 (make sure it has a return port). You "shouldn't" need it however if your car was originally carbureted.

 

thanks, but then do i need a regulator with an edelbrock carb to lower the fuel pressure?...i don't need the return line?
which one?

 

If your fuel pressure is way over 6psi that could be a lot of your problem with the holly.

 

You should NOT need a regulator with a stock style mechanical fuel pump.

 

it's funny; I just did the same thing..went from an holley 700cfm double pumper, to an edelbrock 600cfm.. The major differences is that I felt is?; first the thing was, the acceleration is smoother, but it's still there, the fuel ecomony is a little better. for city driving, but highway driving I sawed no differences. Second( an good) the edeblock seem start easier on those colder days. But really; face it-if your driving an Pony car with an V8, gas mileage shouldn't be that much off an consideration.....

Daily driver; more than 30miles round trip.. 85 T/A, 350 from a 1972, 700r4,9-bolt.dics brake..shorty headers, borla exhaust, gutted cat...but still have my
700 double pumper....

But I wouldn't sell your holley; because of those special days.

 

If you have a mechanical fuel pump, located on the block, you should not need a regulator. If you have an electric, in-tank pmp, you need a regulator with the return.

 

thanks guys for all the help...hey phillyterror,,,i see the same differences..my edelbrock starts easier with little cranking and the choke works like a charm...it accelerates like the holley and no bogging or hesitation,,i like the edelbrock,,,if i get a fuel pressure regualator and set it a 5.5psi like edelbrock suggest even with mechanical pumps , would this be ok?...it would get constant 5.5psi pressure....i know edelbrocks are a little fussy with the fuel pressure...i kept my holley double pumper,,,but i think if the edelbrock runs like this ..i will eventually sell it because it will just sit in the corner of my garage...anybody interested? thankyou for any other info on the fuel pressure issue.....

 

if i get a fuel pressure regualator and set it a 5.5psi like edelbrock suggest even with mechanical pumps , would this be ok?

What would be the point of it? The float valve in the carb should be able to handle the flow/psi of the fuel. If it's unable to regulate itself, somethings a little wrong.

Also earlier on, you said about your Holly carb smelling of fuel. The most likely culprit of this to my knowledge would be that you possibly had your mixture set WAY to rich. Which would cause fuel to be unburnt, hurt your fuel economy, and potentially cause it to pool gas a little after shutting the engine off. I'm not an expert here, just running off what little I'm dealing with and learning as I take the journey into the engine compartment of my 86 305 z28

 

hi, i think my holley was adjusted fine,,it just guzzled like crazy but generally ran fine , as for the fuel pressure regulator,,,edelbrock on their tech website recommends 5.5psi of fuel pressure on their performer carbs for optimal working performance....so if a mechanical pump is pumping a little more,,,then you will have some issues,,so an inline fuel pressure regualtor would keep the pressure constant to 5.5psi...it's about $15 and much cheaper than getting a new edelbrock 5.5psi mechanical fuel pump for $100...easy to install too....

 

I have the basic; factory direct fuel pump on my block..It's seem to do fine, Mine you! It's an every day driver, plus it's all highway driving But even at 75mph..if you punch it, it's there. Sometimes it easier to stick to the basic's. I did not bother with an regulator, simple because.. the more stuff under the hood, the more stuff that could be damage.. Now if it was just an weekend car? I probable go full out with every bell and whistle as they say. But 3rd gen is something you don't see everyday.. And trans am as an daily driver is fun, plus I work in an business setting, so it's going against the grain..not smooth hair, suit, or driving a tinted BMW, thinking that's cool.

 

i know what you mean, i drive the car real hard on the highway and cruise the car on the weekends, it's not a daily driver but not only a weekend car, it's a whenever i want to drive it car!!...i try to keep it clean and keep it tip top shape mechanically...this is why i went to the edelbrock with an electrical choke,,i was just fed up with the holley and it having no choke and having to pull the **** like a tractor from the 60's..and it was really thirsty..i have other things and expenses first in life, i can't fill up the tank everytime i want to drive the car an afternoon!!...the edelbrock carb is good,it gives the perfect performance / fuel economy combination ... i still don't know why so many people either love them or really hate them,,it works for me..

 

been told that holley tune better for higher-end engine..all the top performers use holley. but I noticed that they don't last long before requiring an rebuild. Holley is famous for the the golden rule. if the baby backfire on you, it's done..it never run the same until you rebuild it. The major problem is not the enigne; It's GM small fuel tank, that thing is small, sometimes I think about add an secondary tank.

 

you are so right about the holley's ...all the race oriented guru's out there swear by holley and holley alone , and i think with reason ..they are the best for performance,,but like you said..they are fussy and require rebuilds often ..mine was a gas guzzler and it stank of gas all of the time and hesitated sometimes ..i know , i know rebuild it!!..again?..for the 3rd time?...every 1-2 years it requires a rebuild or some kind of major adjustment...like i said my car is fast as it is and i really don't go to the strip ..so it's fine with the 1405 edelbrock...when i will have to rebuild the edelbrock one day,,,easy, they are the easiest carbs to rebuild.....again , just my 2 cents...

 

, and,

.

First, tune the carb so it doesn't backfire. Not hard - personally mine never has backfired. Second, Holleys have had a check-valve protecting the PV for years, so even if you do get a backfire, it won't blow out the PV. If you have an older Holley, a kit is available install the check valve protection.

Constantly needing rebuild - only if you don't have proper fuel filtering, use cheap/bad gas with no detergent, or leave it sitting with water in the fuel or don't drain it when stored or don't use gasoline stabilizer when stored for extended periods.

Gas guzzler - only if improperly tuned or you have your foot in it all the time. Might not be quite as fuel efficient as a q-jet, but they aren't by necessity gas guzzlers. More often than not it's what it's on or a loose nut behind the wheel that make a Holley use a lot of gas.

 

you know FIVe7 kid,,,,you must have shares with holley , or own part of the company, you constantly defend holleys,,,i can't beleive you are saying that holleys are not gas guzzlers!!.. they are gas guzzlers !!..and everybody i know who has had one or still has one agrees...they do guzzle gas because they are usually installed on high performance engines that give you a lot of power and yes --guzzle a lot of gas doing so!!...give me a break!!..BTW . we are all loose nuts behind the wheel here!!!

 

I have no idea why people have such a hard time with holley's, it seems to me its more the operator's negligence than the carburetor actually being the problem.

As for holley's being gas guzzlers I'm in 100% agreement with five7, again take the time to properly tune and you won't be disapointed.

I managed 18+ mpg in my camaro on the freeway (setup in sidebar).

 

No, I don't have stock in nor own part of Holley. I am only defending Holleys against ignorance. If you read enough of my posts, you'll also realize that I will more often than not say "Keep the q-jet!" when someone wants to remove the stock carb and put on a Holley.

You make my point - like I said, it's more what the Holley is on and how it is used than the fact that it is a Holley.

Perhaps. But, some animals are more equal than other animals.

 

ANY carb can be tuned lean enough for proper A/F ratio and good gas mileage. If you can't handle single digit mileage then keep your foot off the floor. A holley can get the same mileage as a Qjet, edelbrock, etc. Just that when you DO want that extra kick the holley or Qjet would be the better choices over junk carter technology. Oh wait edelbrock is carter's design....

 

Not exactly true. Some carbs by design simply dont work well in light transitional situations and a double pumper carb of any make is just uncalled for on a "mild" engine.



Theres definitely a small but significant advantage in the areas of mileage and driveability with an OE style carb over any DP even in it's best tune.

Criuse and WOT mileage is easy enough to match but you'll still notice a difference around town.

 

exactly , this is what i meant...most double pumpers are installed on high performance engines and guzzle gas because the engine demands this...so a DP holley can't get reaseonable gas mileage around town!!..this is why i switched to an edelbrock on my 350 because cruising around town with a holley DP is just not smart as far as gas mileage is concerned....

 

You are completely missing the point.

If it's the engine a carb is on that dictates how much gas it uses, it won't matter what type of carb you put on it (within certain bounds, like similar CFM between the carbs).

If your DP guzzled gas and the Edelbrock sips gas, the Holley wasn't properly tuned. Period, end of discussion.

 

so you'd argue that a vacuum secondary carb would be fine then? Even if the primaries are essentially the same between the two and the idle restrictors and air bleeds could be manipulated for proper around town driving?

 

Yes the DP could almost certainly be improved over what the OP is seeing but it's still not the ideal carb for a "mild" street motor. I could be off base as to what "mild" means to the OP but going by what I know from this post I would strongly recomend a good Jet or similar carb for this app.



Assuming the primaries are properly sized to begin with thats about it. Between two properly sized carbs I think the issue of mileage is going to be slight but definite. If you are going to be putting several thousand miles on this car and the cam allows you to run a Vac carbeffectively then thats what I would run.

As a rule engines that lack the signal stregnth to make a VS carb work well typicaly lack the signal stregnth to fuel the motor efficently at low RPM. In those cases just getting the car to run at all causes an almost un avoidable part throttle/idle rich condition. And if that's dealt with theres still the generaly sloppy transition from cruise to acel that just kills mileage in stop and go traffic.


But in the case of a radicaly cammed street car the vac carb will kill mileage as a result of its poor street manners. If your constantly goosing the gas in order to creep through traffic you're burning a lot more gas than you should be.

 

We are really mixing apples and oranges here.

Let's assume that:
1) The carb is properly sized (there's no need to argue about whether a 950 Dominator or Edelbrock 550 CFM Performer will get better mileage on a stock 305).
2) Any carb type/brand chosen is properly tuned.

Assuming that, to say that DP Holleys "guzzle gas" is completely wrong-headed.

As for VS vs. DP, see #1 above - an improperly sized carb for the particular engine on which it is installed of either one of those is going to produce poor results. You might get by with a too-large VS at WOT better than you would a too-large DP at WOT, but why would you start with a too-large carb in the first place?

As pointed out, the primary circuits of a DP and VS are basically the same - and the differences can be easily tuned if necessary. The typical street-driven mild engine isn't going to need extensive modification beyond basic tuning (jetting, PV selection, idle mixture adjustment, accelerator pump cam/squirter changes). If more is needed, you're better off getting a carb with replaceable idle air bleeds, idle and PV restrictors, and emulsion orifi. And, if more is needed, you probably don't have a "mild" street engine, and tuning these additional features is probably beyond your capability (dyno and wideband O2 really help that process).

Properly sizing the carb is a critical first step. The reason q-jets work so well is the small primaries keep the air velocity high, which increases the signal at the booster venturi and the fuel vaporization downstream. When you get a carb that is too big for your engine need, you reduce the air velocity and therefore reduce the booster signal and fuel vaporization.

But, a 700 CFM shouldn't be too big for a mild 350. If it guzzled gas (and a different carb didn't), it was improperly tuned.

 

You guys should back off Five7 a bit - he's not a Holley *****. Quite the contrary. This is one of the rare times I have seen him not say "Leave the quadrajet on it". But its because he's just presenting the reality of whats going on, not just talking out his rear.

I've had a CC-Qjet, a normal Qjet, a vacuum secondary Holley 750, a 650 DP, and a 750DP on my 350 over the years, and I've been able to get good power AND good mileage (at the same time) out of ALL of them. Every one. Carbs don't use gas - engines do. The carb only delivers the fuel. If it stinks and your mileage is bad, then its delivering TOO MUCH for your engine. That means its time to tune the carb properly.

Beleive it or not, the carb I actually liked the best over the years was my 750 vacuum secondary Holley (3310). It gave me excellent gas mileage, lots of power, great driveability, and I very rarely ever had to alter any of its calibrations. I think I richened the choke up a little after the snow came the first year. That was it.

 

This thread made me LOL. There are so many misconceptions about holley carburetors. They are great little devices and VERY simple. Tuning them takes time but all carbs need a little tuning to run their best.

I've got 18-19 mpg on the highway with my 750 holley powered 383. Guess what, no overdrive either and 3.23 gears!

 

yes it will!!! i had one on my 86 when i first bought it and the carb itself looked OLD, sitting for a year, towed it to my house, got it started, no hesitation, and lit the tires up out of my street haha theyre really good, i now have the 1406 which is their electric choke version of 1405. you wont be dissappointed

 

hi , you don't need to convince me about the 1405 or 1406 edelbrocks...i start the car and the choke kicks in every time..it always runs the same and i am not constantly adjusting the carb...i don't say holleys aren't the best for performance ...but these edelbrock carbs for the money are a great deal for someone on a budget...very good price/quality combination..i think if i had the q-jet that came with my 350 , i probably would of kept that ..i think q-jets are fantastic carbs ..for me the best for all around driving....but i can't complain about my edelbrock....later.

 

I accept with information:For cheap you can't beat a $30-50 used qjet and $30-50 in a rebuild kit and cleaner. If you get a used one from another vehicle with the 700R4 it should come with the correct TV bracket for the tranny cable.

 

And if you're a smart shopper(cheapskate like me) you won't need the rebuild kit. Its not hard to find a q-jet that just needs to be bolted on and go.