AZ520

Hello!

New member here with a stock 350 with #8 heads. I have been dialing in the edelbrock 1406 on a stock intake. I have a wide band A/F sensor reading off the odd side cylinder bank, it a true dual exhaust system.

I was curious as to what jetting people are using with this carb. After tearing the carb down quite a few time I was happy with the jets, then collected quite a few metering rods , finally found a real sweet spot. Its way off of the edelbrock reference chart. I am reading about 12.6 wot, 13 high speed cruise, 13.5 cruising and 14.5 idle. I can not find metering rod combo that gives a leaner cruise with out going too lean under part throttle.

Here is the set-up that is pretty dialed for my engine:

primary jets=.095
secondaries jets=.093
metering rods= 67x55
springs=- orange or 5 in.hg.

oldcutlass

Which adapter are you running to mount the carb on the manifold?

AZ520

Its a Spectre brand from autozone, it has a composite insert in the middle. On top of that is a edlebrock spacer gasket, about 1/4 inch thick.

olds 307 and 403

Be happy you can get it to run worth a dam, most can't with the Edelbrock carb. Why did you remove the Qjet? They are more adaptable to get what you are after. This adapter?https://www.google.ca/url?sa=t&sourc...sv_Hv8zvHcPNdw Very interesting adapter.

Olds64

C'mon an Edelbrock is just as streetable as a Holley or Q-jet. It's not like he's asking for tuning advice for an 800+ cfm Demon with mechanical secondaries on a bone stock engine.

If the adapter has good gaskets and no vacuum leaks it shouldn't change the way the vehicle runs.

TripDeuces

http://vb.foureyedpride.com/showthre...6-Carb-Read-On

Read through this

Olds64

That's a cool explanation of potential problems tuning these carbs. I didn't know the electric and manual choke carburetors were tuned differently. Thanks for the link.

Lee_A

A few years ago, I bought a '72 El Camino, mild 350, and a 1406 carb.


I also have a wideband (Innovate), and also have a chassis dyno. I have a nice selection of jets, rods, and springs. Like you, I spent a LOT of time trying to dial it in. After a lot of tuning, I also ended up with a combo quite different than what the "chart" suggested. Between tweaking the timing and the carb, I picked up about 20rwhp.


It was still not perfect. It would go lean when I wanted it to richen, rich when I wanted it to lean out... I'd rather drive a double-pumper than to have to use another one of those!


I ended up installing a FAST EZ 2.0, selling the 1406 on Craigslist, and never looking back! Immediately gained 16rwhp over the BEST the 1406 ever made, and AFRs were right where I wanted them ALL the time!

cutlassefi

Kudos to the OP for buying a wideband in the first place, smart move.
Sorry guys but those carbs are junk, that's why I don't use them anymore. I use the Quick Fuel stuff instead, You can change Jets, air bleeds, power valve circuits, and everything else that you need to in order to dial it in correctly and achieve a nearly perfectly flat fuel curve.
Be happy you got this far.

AZ520

Thanks for the heads up about the carb, it runs really good now, but sounds like it has way more potential with a different carb. Wide bands are the only way to go for sure! I mainly posted to help people who have this carb, it took a long time to get it close and there is not much info out there for it on an olds.

AZ520

Forgot to mention the carb came with the engine, its my first v8, always had 4 bangers. I love it!

cutlassefi

I hope you know it doesn't have a clue what brand engine it's on so........

76olds

I'm going to play around with my 1406, since I have 2 of them.
Where did you buy the tuning parts?
The wide band A/F SENSORS aren't cheap !!
Put-r-ther , thanks
Eric

AZ520

One important thing to do is get a fuel pressure regulator and set it to 5 psi, I had the stock pump and it was reading 8-10 psi and also check the float bowl level even if its a new carb, yata, yata Edel says these are very important to have correct.

Any auto parts store can order jets and rods and stuff for you, all the info I read on the carb said they are pretty close out of the box for a 350 engine, but it was way too rich out of the box. You don't have to have a wide band, but it sure makes things faster and easier. I had it laying around from an old from an old turbo project. I am pretty sure for a stock olds 350 you will want to start with the jets I used after that its just a matter of getting the right rod and spring combo. I would not go Higher than 070x057 with the metering rods. Part numbers link:

http://www.edelbrock.com/automotive/...ibration.shtml

Lee_A

Look on eBay for the metering rods, jets, and springs. There were a few specific rods I wanted to try, so I had to buy those new.


In general, the tuning parts for these carbs are EXPENSIVE! I probably spent close to $200 to get all the parts I have.

Olds64

The same can be said for Holley tuning parts. I priced some parts for my Summit carburetor after reading this thread and they were nearly $200.

Makes me think it might be worth while to go to EFI.

Lee_A

The jets are the main thing to tune on a Holley, and you can find jet kits for under $40. Getting the idle mixture and the right jets will make most Holleys run pretty well.


Only some higher end Holley carbs have adjustable airbleeds, but you can buy kits with a nice selection of those, just like the jets.


Buying a selection of squirters can get expensive, but I've mainly tuned squirters to match traction condition at the track. With good traction I'll use bigger squirters, but I'll back off on the size if traction is limited so that I don't hit the tires as hard (less likely to spin).


That said, I LOVE the EFI systems I've done! With the computer controlling timing as well, the overall tune can be dialed in VERY nicely and rather quickly.

Olds64

Truthfully, in addition to any tuning parts one might purchase an air fuel sensor is a necessary tool if you really want to dial in a carburetor. One can only get so far using a butt dyno.

olds 307 and 403

Just like Joe got pissed at me asking about mounts, he has gone over it again and again, why are guys buying these problematic carbs? I get annoyed when anyone buys an Edelbrock carb and then it runs lousy no matter what is done. The Quickfuel and Street Demon carbs are way better for the same money.

young olds

I didn't know people were having issues with edelbrocks, I thought they were the main stream go to easy carb. My only experience has been with 500cfm models though I'm not a fan of edelbrocks simply because they are ugly I've never had issues with them. I'm a quadrajet guy, have one on my blow through turbocharged 350 and just picked up a nice core to use on my na 215 I put together, and have had one on probably every v8 car I've ever owned.

olds 307 and 403

I too run Quadrajets. The only other carbs to consider for us budgetly challenged are the Holley style Quickfuel Slayer series or Street Demon carbs. The ancient AFB carbs the Edelbrock carbs are based on had issues back in the day like vapor lock, made worse by ethonal fuels used nearly everywhere. This post is a good starting point, tuning wise for those who want to bother with these carb's.

young olds

I like quadrajets in any situation they will preform under, a single quad has been known to support 750hp then you can just go duals after that ��. They really aren't a good carb to use for blow through, I've been fighting fuel leaking past the accelerator pump shaft from day one. I think they are a great design, except the tiny fuel bowl, and could keep up or nearly keep up with nearly any other carb when used in proper application, especially on a street car.

Olds64

I had a Q-jet on my 71 98 that I had rebuilt professionally years ago and then I rebuilt it again before selling it. I now have a Summit carburetor (Holley 4010) on my Olds. I ran an Edelbrock 1411 on my 64 98 for awhile and my father and I ran a Holley 4150 on his 69 Delta 88. I've found all of these carburetors have issues from time to time.

There isn't a way you can set a carburetor and forget it. It will eventually need maintenance again. Heck, even with a stock engine that has MPFI you have to de-sludge the throttle body, IAC motor (or Idle Air Bypass) and injectors after a number of years.

olds 307 and 403

The only new carb on market that can offer similar features, excellent fuel economy but still move when opened up, in a new shiny package is the Street Demon. It being heavily based off the Thermoquad, the Qjet's main competition, with it's problem areas fixed and has nearly 100% positive reviews. GM did do blow through turbo's with Qjet's but they weren't too impressive or ran much boost.

young olds

I didn't think they ever did blow through, I've only seen gm do draw through, what car did they make that was blow through quadrajet from the factory?

olds 307 and 403

Sorry, yep different, draw through.

jpc647

what do you mean? The where do you see that an identical carb otherwise except for electric vs manual choke would need different tunes?

Or are you saying the 1406 electric choke vs the 1405 manual choke?

Because there are a lot of difference between the 1405 and 1406. The idle circuits in the 05 are bigger, etc. I never got a 1406 to run right on a stock 350. So I bought a 1405 and swapped the electric choke from the 1406 over from it(Which I don't understand why more people don't do, instead of screwing around with a 1406).

My float levels have been adjusted a couple of times. I still get bogs/issues if I come around a corner fast and hit the gas too much, it feels like the car bogs for a quick second before it catches up. It also doesn't like load at low rpm, like slowly backing up a hill or a ramp, etc.

I think i'm currently at step 11, which is all the way rich in power, and 2 steps rich in cruise mode, and it's about as good as it's been. But I still feel like it's being held back at WOT. IT doesn't bog, it just feels like its being held back. I'll double check my notes a report back.

I've also adjusted the accelerator pump to no avail, and added bigger accelerator pump squirters. I feel like the car is better right after it's been started, when the choke is still sort of active. But I don't understand why that's the case, and Edelbrock tech support has been less than helpful in the troubleshooting. This has been my summed up experience with Edelbrock over the past couple summers.

When money prevails, I'll be ditching it for a Quadrajet.

Edelbrock packages jets, metering rods, and springs together in "calibration kits" for like $40.

76olds

Maybe I shouldn't have bought two Edelbrock 1406 carbs haha, still have the new one in the box.
I suppose I should look into buying a Quick fuel and give my new 1406 away and throw the other one in my scrap metal bin .
What Quick fuel carb would you guys recommend for my killer 350 haha!!
I'm going to buy one and give it a try for the heck of it.

Thanks
Eric

AZ520

I like the way its running now, I do get that sharp turn and then bog, its not terrible, the A/f goes rich, I have a 68x57 metering rod coming in the mail to try next. Its crazy how leaned out the carb is getting. I recommend trying my jet combo if you are near stock, I have tried everything and its getting close. I have spent a small fortune on jets and stuff, lol

jpc647

What kind of vacuum are you pulling at idle? I went with the 8" springs because my car idles around 17" Hg at idle.

You're sure the AF ratio is going rich around corners?

I'm certainly following this thread. It's 8*F outside right now, and I can't find the notes I have on the carb(they are someone in the garage). I'll find them just to tell you where I'm at.

AZ520

Yep its around 16-18 at idle, I read you should get a spring half that, but I have read it should be in drive at idle which drops it to around 12. I always end up going back to the 5/ org spring. Having the A/F gauge really helps to see when the metering rod raises up and goes richer. I found with the stiffer spings it pops up too fast/ early and goes rich at light throttle inputs. It goes rich after turning and getting on it, not full throttle, about 3/4. Sorry made it sound like the corner has something to do with it, its just when you turn and give gas, but not enough to have it kick down the trans.

cutlassefi

750 Slayer.
Again kudos to the op for buying the wideband. Notice how much he's gone thru WITH it. Just think how much more difficult it would be without it.

olds 307 and 403

Mark, 76 Olds is being sarcastic, his 350 has a stock rebuild of his mighty 76 350 with shorty headers and exhaust. He will be lucky to have 8 to 1 compression and the tiny stock cam. I say a 625 Street Demon or the 600 Slayer but I am no carb expert. A wide band is a great tool, takes out a lot of guess work and trial and error.

Firewalker

The common Edelbrock carbs are old AFBs, and are limited on normal tuning like for full power. The Thunders are different and the next stage of the AFBs called AVS giving easy secondary opening control. The third version of the AFB was the Thermoquad, which the Street Demon mostly is.

These carbs for the most part like 4-5 pounds of fuel pressure and no more on the street. You can not tune with a O2 meter to get the strip performance the best. That has to be done the old fashion way of trial and error with time trials.

Want to know how to tune the common Edelbrock then find a book on racing AFBs. One thing to note is needle and seat sizes the Edelbrock and Street Demon's have is only .097 or so, where as racing AFBs and Thermoquads had up to .120-.125 as options, and a .110 in between. They also had more stable brass floats, that didn't soak up gas over time unless they got a hole in them, which a little solder could fix.

All ran pretty good from the factory, but the factory wasn't limited to a few jets and rods, nor to only a few spring choices and the secondaries were already set to open and run right. My choice of the 3 is the Street Demon with the plastic body for cooler fuel and the much much easier tuning on the secondaries. Then the price is much better. Saw some new ones for $220 on Ebay.

For parts I would look at the AFB and Thermoquad parts choices, as many parts will interchange and research might tell you which ones. A nice heat shield is a good idea, especially under aluminum carbs.

All options including Holleys, injection, or Qjets can run perfect, but few do, and all will give you problems over time. They can all run down in the 11s with work or even 10s with work.

76olds

Yes, I'm probably down to 7:8:1 with them thick head gaskets so i was told. Stock rebuild, stock cam so, I think I'll wait until my 350 takes a turn for the worse and needs rebuilding.

cutlassefi

Good info but his problems are mainly part throttle, not WOT. WOT as you know is the easiest to tune.
And you forgot QF and Proform carbs, each of which has replaceable air bleeds, so in case you drill the others air bleeds too big you don't have to go back and replace them.
Finally, injection will ALWAYS work right, and typically with 0 problems. Just look at today's stuff, runs hundreds of thousandths of miles with just an occasional can of cleaner.

Firewalker

I have to disagree with you Mark, but injection is not that reliable at all and anyone working on cars, that has years worth of experience knows it. Go to any part place or dealerships and see what parts they have for the injection systems. Or go to the dealerships and ask to look at their very expensive diagnostic machines to troubleshoot what went wrong this time.

Also their is a huge difference in after market versus OEM and after market is not near as good. Who offers even a hundred thousand full warranty for parts and labor on their kits?? I have both OEM and after market. QF and Proform are just retuned or modified Holley designs, but probably are a better choice than Holley.

His part throttle is mainly controlled by his rod and jets and their are many combos for an AFB. WOT may or may not be easy to tune right and most don't.

cutlassefi

Not sure where you work but I own 5 cars, all of which are fuel injected, and some have 100,000+ miles on them. Never an issue, never.
And yes Proform and QF carbs are "redesigned" Holleys, and imo vastly improved vs a Holley.

Firewalker

From what I have seen the Proform and QF carbs are better and maybe much better than Holley. I have no love for Holley, though I have run 4 or 5, in my long long lifetime, including factory Holleys. Also the first Holley Injection system.

A car may go 100,000 from the factory without injection problems, but so could the OEM carbs many times. There is also a big difference in cost up front, and repairing injection, with many more parts to go out, with all depending on the perfect electrical system.

With a normal carb there are fewer parts that to go out and they are cheaper to buy or repair. I have seen the fastest gasoline cars using carbs. I have seen mega gas mileage 45 years ago using carbs. Instant starting in all weather using them.

olds 307 and 403

Emissions was only one reason manufacturer's went EFI. Fuel economy and drivability went up big time, especially for Ford and Chrysler. Their carbs were junk compared to the Rochester's. Early EFI was a bitch to pull codes out of, crude electronics. Overall motors last much longer now days. I remember a long time Ford mechanic I apprenticed under commented how many less motors jobs there were since Ford switched from carbs. The Olds V8 was one of the few motors to go a few hundred thousand miles without being opened up, except maybe a timing chain. Yes I remember Lean Burn Chrysler's and Variable Venturi Ford carbs, their only 2 bbl carb that wasn't a gas hog, when it ran right.