Hey all, been having problems with my Edelbrock 1406 ever since I got the car a year ago (carb came with car). I have been thinking about getting a new one for some time now, but as I keep being able to get satisfactory performance out of the 1406, I keep putting it off. I am by no means a carb expert, and I have noticed that most of the literature out there (and posts on TC) all deal with Holley carbs. I am just wondering what you all would recommend as a replacement if I decided to go that way. The car is a fairly mild 350 M20 combo with 2.73 rear end (rear end will definately be changed to about a 3.55 over the winter, and the 350 may possibly be replaced with a 383, so would like to keep that in mind with carb selection). Car is 90% street 10% strip.

I have heard good things about the 3310, but I have also heard that vacuum secondaries would be ideal for my application (and 3310 is double pumper correct?), as well as that a 750 carb would be too much for my engine. Looking for a fairly gentle learning curve as far as tuning/tweaking goes.

What are your thoughts? Or should I stick it out with the 1406?
Thanks!
Brad

For a mainly street car with good driving manners, you can't go wrong with a Q-jet.

is there a particular model of Q-jet that is ideal? I see in the Summit catalog that there is a stage 1, 2, and 3 model, with prices starting at $350 and going to $390...

Any other thoughts?
Thanks!
Brad

I'm guessing, now that I have done some more reading, that I would want to go with the stage 1. Anyone else have any opinions on a good carb for my application? Would Ebay be a good place to get a Q-jet? or am I better off sticking to Summit/Jegs?

Brad

If your plan is to upgrade to a 383 in the near future why not go with the 3310VS that way you want be wasting money in the future for a different carbs. The 3310 is a very nice carb for street use and produce some very good number on my combo. I still have that 3310 that was used on a dyno that I bought from Summit (new) if interested let me know, I can save you a few coins.

If you want a good carb for a street car get hooked up with one of the Qjet builders,check for recommendations on this and other forums. There is no comparison between the two. The holley is a very crude design with very little thought given to street manners and economy. It was designed and built originally as a race carb,and later adapted to the street. The Qjet if built properly will out perform the Holley in every way. They do need to be tuned to your combination and that is why I would recommend dealing with one of the top Qjet builders.My $.02

hmmm...so far the responses have echoed what I have been reading, 3310VS or Q-Jet. What are the advantages of the two? What kind of prices are involved in getting a Q-Jet from a builder, tailored to my specs? What about the 3310VS? Does it require the same professional dialing in as the Q-Jet? Or is it something I will be able to tune myself (not a lot of carb knowledge, but mechanically inclined and a quick learner...)? My Hot Rod magazine Horsepower Handbook profiles both the 3310 and Q-Jet, and seconds the need to have a professional set it up, but they seem to like both carbs.

Thanks for any feedback!
Brad

Just a sugguestion but have you looked at Barry Grant Carbs? I am running a BG Speed Demon 750 on my 383 and am about to change to a double pumper. If your motor is a little more mild than mine check out the 625 cfm Road Demon. It'll work well with a mild 350, but keep in mind when you got to the 383 if you have some nice heads and a cam with noticeable itle then you might want something bigger. I tuned my engine on the dyno to adjust the air/fuel ratio and although it is still a tiny bit lean (thus the reason to go to a double pumper) It runs quite well for my combination.

Nothing against a quadrajet, but I think the BG carbs (which are essentially Holley) are a little nicer for a little more money.

My 2C

Steve

Deeboo, I sent you a PM...


Any more ideas? I like the price of the 3310 compared to either the qjet or demon, but of course I would still like to go with the best carb for my application (well, a balance, of best carb/price/ease of tuning...)

Keep the ideas coming...so far it seems that the 3310VS and QJet are the front runners, let me know what you think!
Brad

You never said what your problems have been with the 1406...

I have some experience with a 1406 and a 1407 (600 and 750 versions) and they are good carbs for street and mild motors. If you start pushing up into cams with more overlap they can be challenged at the lower vacuum. But I think they are more tunable than most Holleys and I like that there are no gaskets below the fuel line. There can be a bit more math/science involved in tuning since you have an interaction between metering rods and jets. But setup up a computer spread sheet to make the calculations and this becomes trivial.

I have run both of these carbs on my moderatly tweaked 402 and for the street, in many ways, I prefer the 600 CFM version. It is slightly spread bore with smaller primaries than secondaries. This gives it a smoother more progressive throttle control which is good on the street. The 750 is pretty much square and behaves much more erratically being either on or off.

Note also that these carbs come with lean or performance calibrations. The electric choke versions, like the 1406, are all setup lean. The manual choke versions are setup for performance and several steps richer.

When you get right down to it both the Holley and Edelbrock carbs do the same stuff and really in similiar form, just slightly different ways. The Holley has a power valve to turn on low vacuum/high load enrichment while the Edelbrock has a piston and metering rod. All does the same thing. Both have accelerator pumps and both require them to be setup correctly.

I would suggest buying a couple of tech books on carbs before spending more $$$ on a new carb. After reading and understanding you will have a better idea of what you want and avoid making the wrong choice.

I would love to see how well the Barry Grant Demons with the Idle Eze work with high overlap cams. This sounds like a very good idea.

Personally, and especially with a four speed, I like Holley Double pumpers.
I have a 650 DP on the 355 in my Nova, and it runs like a scalded cat!
It has a great seat of the pants feel, and excellent throttle response.
BUT...I have Fun per Gallon, and couldn't care less about fuel mileage.
You can't go wrong with the 3310 VS for a street car. (lots cheaper than a Double pump too)
They run great right out of the box, with minimal adjustments.
Bolt it on, hook up a vacuum gauge to Maniflod vacuum source, and set the air/fuel mixture screws to get the highest vacuum reading at idle. That's it...DONE.
If necessary, You can fine tune the secondaries easliy by simply changing the spring.
(I would recomed getting the "quick change" kit, with all the different springs.)
The spring controls how soon the secondaries come in. Too light of a spring, and they flop open causing a bog.
I wouldn't rule out a Q-jet, but it seems like unless you know what you're doing, they just don't perform well. I also wouldn't suggest buying a used carb...you're just inheriting someone elses problem
Holleys are simple...easy to tune, easy to get parts for, and very reliable.

Here are a couple of links to carb builders / tuners that can modify a Q-jet to your specific application. I have had two Holleys done by JET Performance and a Q-jet done by SMI. Have had good luck with both of them. The Q-jet is on my daily driver 84 C20 Suburban. Works really nice.


http://www.smicarburetor.com/


http://www.jetchip.com/

great, thanks guys, lots of good responses there. I read through the 3310 manual on the holley website last night, and it seemed a lot more straighforward then the 1406 manual was (I'm sure to people with more experience with carbs they are both simple, but I was able to follow every step of the 3310 setup and tuning procedure...) Jet seemed to be the place that keeps coming up in my research as well. What about SDPC? I see that they have remanufacured ones for $200. If I was to order from Jet, about how much does it add to the price to have them set it up for your combo?

Anyone with more thoughts on carb choice (other ideas, or just a vote for the 3310VS or Qjet) or with feedback to the above questions, please let me know!

Thanks!
Brad

I'm not sure on what current pricing would be from JET, I had an 850 Holley modified by them (Stage 3 modifications) 6 or 7 years ago, and with me providing the carb it was $300.

This last fall I had Sean at SMI perform Stage 1 mods on a q-jet. This is basicly a stock rebuild with a few minor modifcations taylored to your car / drivetrain. With him providing the carb the price was $315.

Installed it, adjusted the idle speed and auto choke a little and it has worked great since. Part throttle and mpg were both improved from the oem carb.

Hope this helps.

just emailed Jet about prices for a 3310VS and Qjet setup to my combo...


Brad

hmmm, $315 for a stage 1 modification with them providing the carb (Qjet) seems pretty good. Hopefully they can throw in their 2 cents about the 3310 or Qjet...

I posted this earlier, but is the 750 CFM going to be way too much for my current setup (I know I want to think ahead, but just curious about how it will work with my current setup)? Since I didn't mention it before, my cam is a 218/230 @ 0.050" and my heads are the stock 1.72 intake/1.5 exhaust. The heads however will certainly be swapped over the next 6-8 months, maybe a set of vortecs? Regardless, keep that in mind....

Thanks again guys!
Brad

A 750 vacuum secondary carb(3310) will NOT be too big for a mild 350/4 speed combo.
Vacuum secondaries only open to what the motor needs,so the engine is never "over carbed"

You can get for one for $250 or so new,less used.

if you want a qjet,read this:

http://www.chevelles.com/forums/showthread.php?p=622109#post622109

thanks Chris, I think I know the answer already from reading previous post by you, but what is your opinion? The 3310VS?

Also, with the 3310, is it as important as with the Qjet to have it set up by a pro? or is it more user friendly such that I should be able to dial it in from known combos and ease of tunability? The 3310 manual certainly sounds straightforward enough.

Thanks again for all the help guys, I appreciate it!
Brad

A 750 vacuum secondary carb(3310) will NOT be too big for a mild 350/4 speed combo.
Vacuum secondaries only open to what the motor needs,so the engine is never "over carbed"
You can get for one for $250 or so new,less used.

Chris,
Scoggin-Dickey still has rebuilts available...
http://www.sdpc2000.com/catalog/1448/Holley-Reman-Vacuum-Secondary-Carburetors.htm

Bill,thats good news :thumbsup:
Brad,IMHO and experiece,you won't need a pro to set up a qjet.
Not a bad thing if you do,but if you don't mind tearing into the carb itself,its pretty easy.
The 3310 I would just run out of the box,other than swapping out the secondary spring to a lighter one.
Remember,3310's where used on 1970-72 350 LT-1's on both 'vettes and Z28's

that is good to hear, I certainly don't mind digging in to one as long as I have some reference material, of which there is lots on the 3310. I think I like the sounds of the 3310 the best, and the price is certainly right, for both the new and rebuilt ones (is it worth the extra $50 to get a new one?). There is no problem just directly swapping the 1406 for the 3310 is there? I shouldn't need any adapters or anything correct?


Again, thanks for the help!
Brad

I would spend the extra $50 unless you you are buying a factory rebuilt one. Most of your vacuum lines will be routed a little differently due to the port locations but that's not a big deal. You can usually swap kickdown studs and such from the old 1406 to the Holley.

Just been doing some more research on the 3310 over lunch. A lot of posts I am reading here and on Team Camaro are talking about the 3310 getting really poor mileage. I understand why this would be straight out of the box, but if the primary jets are changed out for something a bit smaller then the stock setting, is mileage still a problem? As this is a daily driver - don't need to drive too much, as I can walk (and do walk) to most places I need to go, but it is still my only source of transportation - fuel mileage is somewhat of a concern. It just seems to me that as Chris said, with the VS they will only open when the engine really needs it (which will not be when I am just putting around), and if the primary jets are reduced, then I should be able to get resonable fuel economy (resonable relative to the engine). Am I off on this one?

Sure seems that there is a fierce debate about the 3310, or 750 CFM in general on a 350 here and on Team Camaro (from what I have read though, I am in the "750 might be more then enough, but it will only deliver what the engine needs" camp).

Thanks!
Brad

If fuel mileage is a concern, then stuffing the biggest carb on there is not going to get you anywhere you want to be. Especially in the realm of square bore carbs, a spread bore will allow you to optimize both ends of the spectrum a bit better.

It is true that you can run a bigger carb and it will work, but will it work well? With a bigger carb you will see greater and more drastic changes in vacuum and this requires more accelerator pump to work around. And accelerator pump squirts are adverse to gas mileage. Note also that all carbs have a low vacuum enrichment device that will get kicked in a lot more with a bigger carb. Again this is adverse to gas mileage.

All of this is just on the primaries, not the secondaries, so no vacuum setup or counterweighted valve setup is going to help or change it. Once you step on it hard enough to get into the secondaries you probably don't care about gas mileage anymore :)

Nor can you just arbitrarily put smaller jets in to increase gas mileage. Your engine requires a certain ratio of fuel to air (as you know). For gas mileage you can jet/tune to get leaner, but only to a point. If you get too lean, at best it won't run so good and at worst it will break parts. This starts to depend on the stock base calibration and the intended carb useage. Your 1406 is already setup on the lean side of the spectrum for example. I have no idea how the Holley is setup, but if there are complaints about gas mileage it probably has a richer calibration.

Unless you have extra $$$ to throw at parts, you should wait and try and understand more about A) how this stuff works and B) how it is built so you can select the best parts. For example the difference between a 600 and 750 CFM Edelbrock is only in the primary throttle bores, the secondaries are identical. So at least for Performer carbs you are changing the normal operation side a lot more than the top end power operational side when you step from 600 to 750. Are Holley's built like this? How does the Holley bore and venturi size compare with the 1406 you have?

Be honest with yourself about your usage and don't build a race setup when what you really do is drive around on the street. For street performance tune ability is key and one advantage to your 1406 is the ability to tune a power AFR seperate from a cruise AFR. Note if you don't like the tuning directions for the 1406, just use Holley's directions substituting 1406 mechanisms in the same procedure. Or get a wideband O2 setup to use for tuning. That and a vacuum guage will teach you a lot about how this works.

That is probably enough flame fodder for one post. I admit I like the Carter design even though most love Holleys. Besides it sounds like you have already made up your mind on the Holley 750 CFM 3310 and are just looking for validation.

69 or 70 jets would be a good choice for a 3310 on a mild 350

..stock in a 3310 is 72

vrooom, thanks for the feedback. I have actually not made up my mind at all about the 3310 (I just said I liked it the best), it is just that all the feedback so far has been about either the 3310 or the QJet, so I obviously am going to be leaning towards one of them.

Also, I am by no means looking to get the biggest carb I can and pretend I have a race setup, if that is what it sounds like, let me clarify - the car is 90% street 10% strip, and by that I mean that I really want something that is fun, but also easy, to drive around town, as well as one that I will be able to tune easily (I think I mentioned that too...).

So, as my original post mentioned, is there any more ayes for sticking with my 1406? I guess maybe the better question to ask in the beginning would be - what would give the nicest balance of driveability most of the time, but with the performance that everyone here would want in a street car, when I put my foot down? A properly tuned 1406? A properly tuned 3310? Or a properly tuned Qjet?

Thanks again for the feedback!
Brad