Well I found out that my Chevelle almost certainly needs a new carb. What company makes the best carb in everyones opinion? I dont want to deal with holley again, because they shafted me on this carb bad.

I was thinking of ordering a demon, but before I spend another $400, I want to make sure I dont have a 10lb paperweight for my money like my street avenger was.

Its for my 350, 280 duration, 492 lift cam, 10.4:1 compression, vortec heads, air-tap intake, 2400stall converter.

Watch out, there are more opinions than there are carbs available...

It really depends on What you want for the car (type of driving/racing you do), the amount of money you want to spend (totally) and your tuning experience or willingness to learn...

first off, EVERY brand has their 'lemons'. You had a bad Holley, some people have bad experiences with Edelbrocks, I am sure there is someone out there that couldn't stand the Demons. I have seen far more bad Holleys, but then there are more of them around too. I have only seen one Edelbrock where my friend just couldn't get it to run good, but countless other Edelbrocks that ran great right out of the box.

Don't let one bad carb change your opinion of the entire brand/company.

I have no opinion about the Demon-brand carbs, but I thought they were basically a Holley redesign, like the Edelbrock is a redesign of the old Carter AFB... If you had trouble tuning your Holley, why would the Demon be any better (unless it truly was a defective carb.).

From your engine specs, I would think a Vacuum secondary version would be best suited. With a smaller, milder motor (350) and a mild stall (2400 RPM), a Double Pumper (Mechanical Secondaries) isn't needed, and the DP won't gain any performance over a PROPERLY TUNED Vacuum secondary.

The Vacuum secondaries will yield better driveability and mileage compared to a DP. The DP only begins to make a performance difference when the engine can use all the fuel available such as launching a racecar at 4500+ RPM, or wide open around a road course in a Z/28.

Go to the racetrack, and you will see almost every racer runs the DP, but I doubt you will find anybody (a pro/semi-pro racer) running a 2400 RPM stall speed, etc...

Why do you think Chevrolet used the VC on all the L78/L89/LS6 cars? None of these used DPs...

That doesn't mean they can't work on the street, just not the best choice...

And once again, I stress PROPERLY TUNED. There are always people out there that swear their DP has more performance than the VC they tried... I am talking real ETs, not "seat-of-the-pants" feeling from the secondary accelerator pump shot... People "feel" that secondary shot, but they often don't realize the car often "lays down" after the shot is done... The VC opens as needed...


At your performance level, you won't see a difference in a properly tuned Holley versus Edelbrock carb either.

The Edelbrock seems more forgiving, and easier to install/initial startup, but the Holleys are so popular that there's lot of folks that have experience tuning them. They are all pretty easy to tune, but it depends on what you are used to tuning...


So, IMO, for most street cars, especially mild ones, I'd go with the Edelbrock.


Here's another thread from just the other day:
http://www.chevelles.com/forum/ultimatebb.php?ubb=get_topic;f=4;t=021385

There are really no bad carbs if you stay with the main manufactures. Some exception has to be given to old worn out stuff...

Don't take this wrong but 90% of the time it's the tuner not the carb. From basic tuning so the engine runs properly to performance tuning to get the most out of your engine. People don't take the time to understand the carbs circuitry before turning screws and changing jets. This causes most of the problems and is really evident when you hear someone being frustrated by a brand new carb.

Save your money, unless your Avenger is physically damaged there is nothing wrong with it. You need to put it back to factory spec's and start fresh. Check this out it may help you www.camaros.net/techref/series_2.html (http://www.camaros.net/techref/series_2.html)

Originally posted by DjD:
There are really no bad carbs if you stay with the main manufactures. Some exception has to be given to old worn out stuff...

Don't take this wrong but 90% of the time it's the tuner not the carb. From basic tuning so the engine runs properly to performance tuning to get the most out of your engine. People don't take the time to understand the carbs circuitry before turning screws and changing jets. This causes most of the problems and is really evident when you hear someone being frustrated by a brand new carb.

Save your money, unless your Avenger is physically damaged there is nothing wrong with it. You need to put it back to factory spec's and start fresh. Check this out it may help you www.camaros.net/techref/series_2.html (http://www.camaros.net/techref/series_2.html) the carb is still at factory settings, and I just cant get the car to accelerate without stalling. There is a highpitched whistling from the carb, and i've talked to a few people and lots of people are having problems with internal leaks and cracked housings with the new holley street avengers. Looks like I am one.

I am old school, any reasonably mild street motor runs better with a Q-jet.

Originally posted by DjD:

Save your money, unless your Avenger is physically damaged there is nothing wrong with it. You need to put it back to factory spec's and start fresh. Check this out it may help you www.camaros.net/techref/series_2.html (http://www.camaros.net/techref/series_2.html) DjD is exactly right.

In addition, how old is your Holley? If it IS a lemon, why not send it back and get one that works? I would imagine that it has a 1 year warranty. Holleys are so simple...If was you, I would tear it COMPLETELY apart and rebuild it. ONe thing I would do is be sure to check all the metering surfaces with a straight edge, spray carb cleaner into each and every single hole with a straw, and make sure it shoots out. Maybe something was lodged in there from the manufacturing process? When reassembling it, just make sure all the tiny gaskets and stuff are in there (like the one under the accelerator squirter, etc). Is your car hard to start when its cold or hot? Are the plugs full of gas? Leave it sit overnight, take the carb off and check the intake. If its leaking internally, it has to go somewhere.

I had a internal leak on a Holley, and it wound up being that metal plate on the secondary plate. It was MY fault- I bent it with a screwdriver taking it off. Why not take that carb apart and check the throttle body, main body, metering block for cracks? What have you got to lose? It cant run any worse than it does now, right? Have you called Holley and talked to them?

I have had super luck with used Holleys, but If I ever bought a new one, I would go ahead and take it apart to look it over, just in case.

I say Holley is the best carb. Its proven itself since almost the literal inception of hot rodding, and still proves itself. Demons, IMHO, dont differ enough from Holleys basic design to be thought of as really anything more than a tricked out gussied up Holley. That is IMHO. Edelbrock carbs, I dont know. I have only used Holley and Qjet. Its hard to beat a Qjet on the street, so I guess you can count GM as a carb manufacturer tongue.gif

One thing that irritates me about Holleys is their advertising today. This "bolt and go" crap is a joke. There is no way all the carbs are suitable for any engine. They ALL have to be tuned to their application. That advertising is particularly true for the Avenger line, and I think it is stupid.

IMHO, Holley carbs are great, their fuel pumps (at least the mechanical ones) well.... :rolleyes:

I'm running a combo pretty similar to yours, including 2400 stall. I bought the following Holley 650 with vacuum secondaries.

http://www.holley.com/HiOctn/ProdLine/Products/FMS/FMSC/0-80783C.html

I had to increase the accelerator pump discharge nozzle from .028 to .037 (with hollow screw) and the initial hesitation on WOT acceleration went away. I also jetted it up from 67/73 to 69/75 which picked up my 1/4 mile trap speed a bit. It now works mint.

This carb comes with electric choke, and a metering block on the secondary side. The photo seems to show a metering plate on the secondary side, but I was pleasantly surprised to see a metering block when I took it out of the box. I paid $318 at Barnett Performance in Atlanta.

I posted this in your other thread but since sending it back to Holley has come up, here it is again...

Originally posted by DjD:
I'd show them this... http://www.holley.com/HiOctn/TechServ/TechInfo/SAWrrnty.html

If you have the reciept it shouldn't be a problem getting the defect corrected...

Yeah! What my former neighbor Fuedo said!

Edelbrock Q-jet for street engine. Small primaries for around town driving and cruising. Huge secondaries for when you need to prove it's a muscle car.

A good Q-jet on an engine that can handle it,...when those huge secondaries open can really feel almost like you downshifted when flooring it ...that front end will come up big time.

I am not a fan of over-carbeurating an engine by guys thinking bigger is better. Tests prove that theory to be wrong. Match the carb size to the engine.

Hey Fuedo, next time you go by Bay point tell them I said "hi". Grew up there and our teams played Clayton, Ignacio Valley, etc. I cruised Wlnut Creek in the early 70's. As close to American Graffitti as you can get without going to Modesto. Almost went to DVC myself. Some good car expertise in the Concord area. Tognottis still there?
Steve

Originally posted by DjD:
I posted this in your other thread but since sending it back to Holley has come up, here it is again...

</font><blockquote>quote:</font><hr />Originally posted by DjD:
I'd show them this... http://www.holley.com/HiOctn/TechServ/TechInfo/SAWrrnty.html

If you have the reciept it shouldn't be a problem getting the defect corrected... </font>[/QUOTE]Well thats interesting, they told me it only had a 90 day warranty... :rolleyes:

I'll be calling THAT number tomarow for sure.

I probabily saw you in Creek. I had the 66 Big Block vette.

I went with a Holley from Bigs Performance. I'll let you know how it works out, but I was impressed with their responsiveness - I STILL haven't heard back via emails from Holley or Demon from about 2 weeks ago.

I like the Holley's because I am very comfortable with them. Quadrajets are also pretty easy to work with, but I'm not as familiar with them. I like the LOOK of the Demons, understand they are similar to Holleys and a bit more tunable.

Hopefully you'll get a replacement Avenger that will work perfectly for you. Good luck!

Is a Q-Jet too big for a 283 with a mild cam? I have headers and a dual 2-1/4" exhaust if that matters. This is for pure street use.

Thanks.

I run a Q-jet on my 86 Cutlass with the mildly built 350 in it. It runs great, never had any major issues with it. It doesn't flood or load up while at an idle and when you get into it, the secondaries open up and it takes off just like it should. Other than that, it does the famous quadrabog noise that I personally find very amusing smile.gif . I am going to be putting a 4 barrel intake and a Q-jet on my 69 over the winter to hopefully improve the gas mileage a little over that 2 BBL. I may add chambered exhaust to it too :D .

Ok, now my little 600cfm carb has acquired the death whistle as well. graemlins/angry.gif

I think its time for an edelbrock.

If two carbs are doing the same exact thing, its NOT the carb. It may be convenient to blame Holley, but.....

Sounds like a vacuum leak to me. Have you check out the engine with a vacuum gauge? Cars get most frustrating, IMHO, when you just throw money at them hoping it will fix the problem. Once you get it ironed out, you will wish you kept the Holley on there. There is NO CHANCE both carbs are bad from the factory.

No, the 600 ran fine for a few weeks now, now it whistles loudly when you give it gas. Sounds like the interceptor from Mad Max.

I agree with buzz, there has to be another problem. Do you have a mechanics stethoscope so you can pinpoint the sound? Have you checked the entire motor for vacuum leaks? Did this problem start when you put the new avenger on it, if so start there. Go through and check everything you did, I'm amazed at how often I find one little thing inadvertently missed, but causing big problems. I would check it over and maybe have a knowledgable friend look it over, if you've been staring at the same thing for a while you may just miss it but new eyes may pick something right out. Anyways good luck,Jeff

I love my $179 remanufactured 3310 Holley from Scoggin-Dickey graemlins/thumbsup.gif
(same warranty as new)


took it out of the box,changed the secondary spring,and adjusted the floats (not too far off either)
Been working great for 3 years..plenty of track and street use.
It was actually worth 1 full mph over my double pumper of the same cfm in similar weather and traction condtions.

Sorry you're having such troubles. It really does sound like a vacuum leak to me. You said you got a gauge to test it. Did you get any readings from it? You can plug it into one of the ports on the carb and check there, and then plug into one lower on the intake and check that as well. I think one of my manuals shows what to look for. One thing you shouldn't see is a shaky needle. I don't know what average readings would be for your cam setup.

You don't have any kind of spacer or think gasket between the carb and intake, do you? Check the base of the intake and see if it is damaged in any way. Have you tried spraying carb cleaner around where the intake seals to the heads and at the front and back while the engine is running?

These things are very frustrating. Best of luck.

Oh, and do you have power brakes? Another source for a vacuum leak. What about the trans line? Has that vacuum line been checked. It can't hurt to rule them out entirely.

When I put a vac guage on it... its very shaky.

With the street avenger it bounced between 10 and 13.

With the 600 on it, it hovered around 14.

Originally posted by Moloko:
When I put a vac guage on it... its very shaky.

With the street avenger it bounced between 10 and 13.

With the 600 on it, it hovered around 14. Bouncing at idle is a sign of a vacuum leak or a carb needing adjustment... If it does the same but intermintantly it can be a sign of a miss, sticking valves. Since it only bounces on one carb I'd say vacuum leak and adjustment.

It bounces on the smaller carb too.. just not as much.

Dominators are the best carb :D well, the name is bitchin anyway!

As a former parts slinger, I can tell you that one of the frustrations of a parts counterman is when a do it yourselfer will bring a part back - replacing it several times - swearing that they were all defective. Statistically, the chances of you being the person with not one, but two, whistling carbs is pretty slim. I'll suggest what I always suggest in such a situation: you need to see a professional mechanic.

Your combo should be happy with a wide range of regular carbs. A good old Carter 600 would be plenty, and super easy to tune - actually I would be suprised if a Carter 600 would need any additional setup for your engine.

Good luck, Thomas

Edelbrock...Edelbrock....Edelbrock...Edelbrock.

I have tuned everything mentioned here since 1965 on just about every combo one can think of. Full race, high performance, mild performance, moderate performance and stockers. You name it...I've tuned it.

The Edelbrock is the easiest to understand and tune, most temperature stable, best metering, and most reliable carb going regardless of the mechanical secondaries. I have had many Holleys over the years but never a real fan. Too many leaks, drips and the old power valve issue (now fixed apparently) and poor gas milage compared against the AFBs. I have dynoed engines with both comproble carbs without a discernable difference.

I made the mistake of putting a Road Demon on my wife's 69 Camaro. I like the looks and throttle response but have been stuggling with the four corner idle everytime the temperature changes. I even thought it was me and had the car up to their factory so they could set it up. My set up was right on......so I don't know what's up with that. The RD will be taken off this winter in favor of a new Edelbrock 750 when the new four speed auto goes in.

I will say that certain specs like one carb or another. I know guys that have Holleys that are absolutely giddy over their performance.

I vote for Carter/Edelbrock.... based on experience from the 50's (when the Carter AFB came out) to the present. Easy to tune... responsive and trouble free.
The only bad one I had was cracked in the base due to some goofball tightening it a bit too much.... (me)

'bear

Just checked for vac leaks, turned up zip. I sprayed the hell out of the engine with carb cleaner and the tone never changed.

BUT....

I checked the timing, as usual I couldnt get a reading with my crappy gun. For ****s and giggles I started plugging the inductive clamp onto other wires. On wire 5 I got a perfect, flat, visible timing mark. Sure, it was like an inch under the timing tab, but it was perfectly visible. I have this strange feeling that means the distributer is not in right. Am I right? No other wire gives a timing mark other than plug 5.

What kind of plug wires are you running? Seems funny that the number 1 wire wouldnt give a reading if its firing? I dont know what would cause that, someone Im sure has a theory.

Are you running a PCV valve? Is it seated right? As for your carb whistling, have you checked usenet? Type in whistling carb or something, and see what it comes up with. I did it, and there was just too much to go through. All Carbs work on teh same principles really, so dont discount advice given if its not a Holley. Everything from loose intake to vacuum leaks is on there.

By the way, just because you hear a whistling sound that SEEMS to be coming from the carb, doesn't mean that is in fact where the sound is coming from.

Check around any and all vacumn lines AND the fittings. You may have bumped/cracked a vacumn line or fitting during all your trials and tribulations.

If that leads nowhere than I would again recommend that it is time for a professional mechanic.

Screwed up plug wires can cause a variety of maladies - none of which involve whistling sounds.

Thomas

The plug wires arnt screwed up, I think the distributer is in completely wrong.

I give up

Justin, try trading two wires with one of them being #1 and see if the problem moves with the wire. It really is a good idea to invest 20 bucks at sears for a mechanic's stethoscope.

Side note, I'll give ya 50 bucks for that busted carb. :D

Its not just that wire, No other wire shows a timing mark but #5. Im going to either take it back to the guy who put the distributer in, and have him check it out, or invest in a quality timing gun before I go messing with timing.

Are you hooking the light at the plug? If so it is probably a slipped harmonic balancer if #5 is closest to the timing mark.

Do the other wires at least make the gun light turn on?

yes, the others turn still make it flash.

" dist not installed right" If you have #1 at TDC and the dist rotoe points at the cap position of where you have the #1 wire,and you have the correct firing order of the wires. I don't care of # 1 faceing the firewall or the drivers fender..it will work A-OK.


Start from scratch ..removel ALL the vac lines. trans,pvc,boster,dist and block off all the vac access tubes.
I like to use a samll hand held propane gas bottle with a ruber hose atached to the burner end, and with the eng running probe all the sealing areas around the intake and carb.
If no leaks are found and you probed around the bowles and base and intake sides and bolt area and the "wisling sound " was still present. I would be at a loss as to where it was comming from.

again go back to basic/scratch.. position #1 at TDC.. check timmming mark on dampner check rotor position in relatiion to the #1 wire.. ????