Carter Comp carbs.

[fatride]

It's funny when you get to tear some of the parts you buy on ebay apart. I have to run specific jets and metering rods in my 600 cfm Carter Comp Series carbs for the 409 dual quad setup. When I tore the first carb apart to change the jetting and rods I found that the default jets were in place but someone had replaced one of the metering rods with an Edelbrock piece. That is ok cause we know that the Carter and Edelbrock carbs are one in the same. Where this goes wrong is the metering rods were not even close in size! I wonder if the seller sold the carb because they could not get the engine to run right??:dunno I have three more carbs to tear into. I hope between those three I can find the right jetting and correct size metering rods.

[Ronnie Russell]

Ray, I have jets and metering rods out the kazoo. Holler if you need something and I will stick em in the mail. models found me a pair of Carters on e-bay a couple of days ago. When they get here, im gonna check em out, and if there is a problem, I know ole models will send me a refund. :brow :brow

[models916]

Refund? What's a refund?

[fatride]

Ronnie, same here, I have four of the 600 CFM # 9605S Comp series. If you need the .100" jets I am going to end up with 4 of these. I need Four of the .086 jets now. I'm just getting into the carb setup and need the 7047 metering rods that Curt Harvey recommends. I have the Carter 16-241 rods and think they are the .0705/.047" but haven't confirmed this yet.

[Ronnie Russell]

Ray , the 70/47 rods are standard rods for Edelbrock 600cfm-manual choke. I think you are correct about the 241 rods, but will check it out in a short while. Over slept because of that stupid hydraulics discussion. :)

[SS425HP]

Ronnie, did you oversleep and miss work???????????:rofl :rofl :rofl

[tripowerguy]

Ronnie are you saying that math makes you have sleepless nights. :rofl Roy

[Ronnie Russell]

If you dont use it, you lose it..... Ive lost everything!!!!!!!!!:rofl

[Ronnie Russell]

Ray, the 16-241s are indeed .0705 x .0475 Ive always been afraid to lean 3 steps. Std jet .095 then .092 .089 .086 . Realize you are getting suggestion from people much smarter than me, but that seems to be on the edge. Dont want to see ya hurt that "sweet thang". Good luck.:)

[fatride]

Ronnie, gleaned that jetting info from Curt Harveys site. I'm lost as to what jetting to use and needed a base line. As for Curt knowing more than you ? I wouldn't take a bet on that. Wouldn't take much to out gun me when it comes to jetting dual quads for my 409, now if it's info you need on three twos :brow Maybe Curt jetted for power on the engine dyno pull and not the real world. I know there is a difference that could make jetting wrong in both cases. I want to hear what others have found. How about it guys, what is working for you?

[dq409]

Ray, Thanks,,, I spend my days brain power allotment on your other post :takethat

Now i gonna be dumb the rest of the day :bang

Curt's recommendations are a good starting point but,,,,,,,, I`m WAY up from those jet sizes and I think you will be also.
I would change all my jetting to Edelb specks as their reference chart is really easy to follow and their parts are easier to get.

My sizes are meter rod 7342 with 98 prim jet and 104 sec jet with a silver spring.

good luck,,,dq.

[fatride]

Thanks Jim, I need more imput like this. I'll study on it some more before I make the final decision.

[Skip FIx]

Guys after buying a wide band AFR meter I've found all of the Quadrajet jet/rod combos that the Pontiac guys swear by for specific combinations are way off. Even Holley jetting from a similar combimations is way off. Each motor even though close in specs has it's own differences in head flow,cam, and exhaust systems to need a different fuel curve.

Alot of the chassis dynos have them, it's worth your while to dial in carbs and timing on one.

[fatride]

Ronnie, I think you misunderstood my post about the .086 jets. I will be starting my jetting with a .095 primary and a .086 secondary with a 7047 metering rod. Does this sound more like it? Or did you know I was talking about the secondarys? If not what do you suggest I start with? One of the carbs came with .100 primarys and .095 secondarys with a 16-241 rod. Maybe I ought to change the secondarys and primarys around and start with .095 primarys and .100 secondarys with the 16-241 (7047) rod!

[Garbageman]

Ray, I also followed Curt Harvey's recommendations for my setup. I haven't the equipment, knowledge or money to experiment away from those settings, yet. :dunno
I've run the car on the streets and on the track and judging from the color of the plugs it's running just fine. I want to find a chassis dyno to do some fine tuning but haven't found one yet. (Jim do you know of one in Portland?)

I'm chomping at the bit to get the old girl into the 12's but so far I'm running consistent at 13.3 with wild runs at 13.0. Still not bad for a 409 with only a .10 over and hydraulic cam with full interior and a garbageman grabing gears.

Paul

[fatride]

Paul, thanks for your input. What your saying is, you are running with .095 primarys and .086 secondarys and a .0705/.0475 metering rod. Correct ? Do you see where DQ is running a .104 secondary jet? It's tough trying to establish a base line for jetting with all the different setups we are running. Kicking the tranny into nuetral is a nono when you are running an automatic so reading the plugs is probably "out" when at the strip.

Ray.

[Ronnie Russell]

No Ray, I did not mis-understand . No way could you use .086 in the primaries. I knew you were talking about secondaries. The last several sets of 600s I have worked on were Edelbrocks. Should be no differance with the Carters. The man. choke versions come with .100 pri, .095 secondaries. (.070x.047 rods) The best combo I have found for dual purpose is .095 pri, retaining the .070x.047 rods. and .092 secondaries.Then you can change to .073x.052 rods to lean another step if you like. That is why I was so surprised about Curts .086 sec. jets. But again, HE IS CURT HARVEY. Its a pretty funny subject with dq usin .104 sec jets. We are all over the place!! It seems logical to start at 1 or 2 steps lean and adjust from there. Since Curt suggest .086, maybe you will want to split the differance and go with .089 sec. And dont be fooled by plug color after a cruise around the block. Even correct jets will darken at low speed. True color shows after WOT. Hope I haven t confused. Good luck.....

[dq409]

The way I got to the combo I have is running at the strip and adjusting the jetting by the times i was running.
Jetting up was getting better times with each increase.
You are correct in only changing the jetting a step or two at a time then seeing what the difference is on the times run.
Also do one type of change at a time so you know what worked and what didn`t.
If you change more then one thing at a time you don`t know which one did what.
ie: timing, jetting, launching etc

Ray , you can shift to neutral at the end of your run and coast to the return lane then pull your plugs and check them. I`ve done this several times over the last few seasons.
Did you get that ref chart I emailed you?

Paul, There are several chassie dynos in the portland area.
I`ll get you some numbers, dq

[fatride]

No way am I confused, I'm eating this stuff up. This is much needed information keep it coming guys. Thank you Ronnie, you'll have the chance for a hands on jet change at Clay City, I could use the help.

[fatride]

Jim, my tranny guy says that you should not kick the auto tranny into neutral at the end of the run, he says tranny will go into hyperspin inside at that speed and frag something. :dunno

[Ronnie Russell]

Ray, it would be an honor to stick my head under your hood.:rofl After last re-build on the glide, trans. man said to never warm up rear end on the jack again. Something about trans. damage. I know nothing about A/T so I cant comment. But we now run up and down the return road to warm rear end.

[Skip FIx]

A friend from Tampa has a 64 409 race car that fraggged a TH 400 going into neutral at the end of the track.

[SS425HP]

Had a friend, Dean LaPole that stuffed a TH400 into reverse at the 1/4 mile. Had to. Was on fire. Chutes burned off. No brakes. Stuffed it into reverse at 200 MPH. got stopped, too. Didn't hurt the tranny. His fire suit and underware were JUNK. 1970 at Lion's drag strip. Saw it.

[fatride]

When you purchace a strip kit for dual quads you buy two right ? :scratch

[Garbageman]

Yes, those are the sizes I'm using.
You have to remember Jim is running Edelbrock Thunder Series AVS carbs not AFBs. This allows him to adjust his secondary air valve to compensate for a lot of changes.

But I agree that with steady increases or decreases in jet size at the track you can see definate results. I guess I'm going to have to pry open my wallet and get a couple of tuning kits for this season.

I did have some good news today. Long story short:
Last year at the track I dropped a valve--only damage was to that valve, spring and guide. Had a shop (drag racer also) repair the damage installed better locks and thicker walled pushrods ( mine were bending) added screw in studs and life was good. :)

Raced the rest of the season but performance was down. Pulled valve covers--pushrods were deflecting the rockers side to side:eek: Went back to the mechanic and he said the machinist had oversized the Pushrod guide holes in the heads:cuss An argument insued. I called Phill and got 3/8 in pushrods and guide plates.
Today it was warm enough to drain antefreeze to pull heads for guide plate installation (milling involved).:cuss But before I got the heads off I tryed the 3/8 pushrods and THEY FIT PERFECTLY. NO NEED FOR GUIDE PLATES.
I'm assuming when the mechanic told the machinist he was installing thick pushrods sohe thought 3/8s instead of thick walled 5/16s.

I'm a happy camper now. Any one interested in a set of thick walled 3/8s Smith Brothers pushrods?
Paul

[dq409]

Yes, those are the sizes I'm using.
You have to remember Jim is running Edelbrock Thunder Series AVS carbs not AFBs. This allows him to adjust his secondary air valve to compensate for a lot of changes.

Paul

I don`t think the AVS`s adjustable secondaries have much to do with jetting.
They only allow you to adjust the timing of the secondaries opening.
If I remember right i was really close to these jet sizes in my old Edel AFB`s.
I think they were up to .098`s, dq

BTW, Glad to here about the head work/push rods!

[fatride]

Jim, what were the issues you were having with the AFBs that made you switch to the AVS carbs?

[dq409]

BOG Off the line. If you watch the convention video you can see that my car bogged off the line then the next pass was better. By the time the third pass I had it dialed in.
it only takes a second to tighten up the secondaries with the AVS`s.
Can`t do it at all with the AFB`s.
before the convention here in Portland I had the carbs running without any bog but at Thunder Valley it came back. Don`t know what the problem was but with being able to tune the secondaries it wasn`t a problem.
I screwed with the AFB`s for a long time tryng to get the bog out but never could.
I would recommend the AVS over the AFB`s anytime.
The small price difference is well worth it.

Paul is going through this and has been the last few seasons. I keep telling him to up-grade to the AVs carbs but he just don`t listen :D
must be something about living in a rain forest:eek:

[jim_ss409]

I'll try to remember to bring my notebook home on Monday. I've got my jet and rod sizes written down in there. I've got a wide band fuel air meter and I found that the richer I went, the faster I went. I started out averaging about 13 to 1 and I think I was at about 12.6 to 1 on my last run. By the way, I'll have that meter with me at Clay City if anybody wants to check their Fuel-air ratio we can hook it up. You've got to install a bung in your exhaust in order to do that though. I think it's the same bung that's used for a typical O2 sensor on most new cars so they're readily available. I'll find out the size Monday and post it here. :cheers

[Garbageman]

I did get rid of the bogging problem last seaston. I switched from a stock fuel pump to a carter street/strip pump, problem solved. Really. Jim saw me run one pass last year were the car bogged but that was driver error, not enough rpm. Really.
Ray the AFBs work fine
Yes the AVSs work better
But where's the challenge? If it was easy everyone would do it.:rofl
Good luck. I'll keep you posted on my tunning efforts.

[Ronnie Russell]

The AVS is an old design. Late 60s, I believe. Chrysler products. Adjustable secondary air valve and 3 step metering rods. The best damn AFB ever made. Dont know why Carter dropped it. Must have been financial. Bring it back 30 years later and call it "revolutionary improvement". Not sure if the new ones have the 3 step rods, but I hope so. Has to help fuel economy, especially in a single carb. set-up. But as Paul said, AFB works fine, AVS works better. Ive never had bog with the AFBs but the adjustable sec. air valve is nice to have in case one has that problem. Jim justs likes having the best. :beerbang

[dq409]

Jim justs likes having the best. :beerbang

Partly true,,, but as Garbageman said, it is the launch rpm that causes/cures the bog.
Each engine and combo will create different problems. For some reason this engine of mine loves to suck the secondaries wide open from the gitgo.
If I launched it at the prefect RPM there was not a problem but a slight drop in RPM it would bog.
In using the brake launch method it was really hard to hold the car back and achieve the required RPM. I tried everthing to get the AFB`s to react slower but could never get them right.
Now with the AVS carbs it`s not a problem at any RPM launch. I can adjust the secondaries as tight or loose as need be.
If there is a better designed performance part availible for a resonable upgrade price why not get it???

Isn`t this what we all want? Adjustability ? Ease in tuning?

I went from a 12.99 et to 12.3 after changing the carbs.
In my opinion the AVs carbs are better all the way around.
From talking to the Edelbrock reps at the races they say that the AVS has a better fuel metering/delivery design then the AFB`s.

I for one won`t go back to the AFB`s,, :D ,,dq

[models916]

You can by bigger squiters for the AFB. Tune the secondary opening with weights on the top flaps. It's just counter ballanced. Add weight=slower opening. Still, a bog is a lean spot, cure it with fuel. If the engine is pulling the secondarys open it wants air, just give it a richer shot.

[dq409]

You can by bigger squiters for the AFB. Tune the secondary opening with weights on the top flaps. It's just counter ballanced. Add weight=slower opening. Still, a bog is a lean spot, cure it with fuel. If the engine is pulling the secondarys open it wants air, just give it a richer shot.

True but false,,,, Try adding or removing weight at the track. not that easy or fast.
A small wrench and screw driver and literally a few seconds and the AVS is re-tuned.

You are some what right and wrong on the bog. If your secondaries open too soon it will bog big time.
I`m not saying that the AFB`s are a bad carb what I am saying is that the AVS`s are better when it comes to tuning in the secondary flaps.
With the design of the AVS all the tuning is done with the tension spring screw . no guessing on how much weight to add or subtract. What do you use for weights? how to keep it in place? Drop them down the carb !!!
Pain in the a** if you ask me !!

Why not up grade if and when you change carbs?
Why not go for something that looks the same but is a better design?
Seems to be a no brainer !!!:deal

[Ronnie Russell]

dq, "seems to be a no-brainer". Money!!!!!!! There are a few of us of this web-site that have to pinch pennies. As I said, the AVS is better, but I can make the AFB work just fine. And besides , You need adjustable sec. air valve to tune often because of those "paint buckets " you are using for secondary jets!!!!!!!!:rofl :rofl I know,,, e.t. slips dont lie. Cannot argue with you there, but with .104s, that air valve better kick open REAL quick. :brow

[dq409]

You need adjustable sec. air valve to tune often because of those "paint buckets " you are using for secondary jets!!!!!!!!

You can talk penny pinching because thats where I`m at most of the time.
I did say when you are changing carbs or in my case having a bog problem that these carbs will help cure.

I bought the AVs`s then sold the AFB`s at a swap meet and did fairly well on them.


On to jet sizes,,,, Like i said I increased sizes one to two steps at a time to get where I am.

NOW,,, what are you other guys using ??? Are mine that far out there that I`m gonna get a razberry over them???:rofl

[SS425HP]

Jim, nobody is going to Razz you over a couple of sewer drains!!!!!!!!!!!!! Don't you have any vacuum? The fuel just has to fall out to get there?:rofl :rofl Ronnie, did you have fire hoses that big?????????????????:scratch How much fuel do you use on a pass?????????


















































Just kidding, Jim

[jim_ss409]

The last time I was at the track it was a cool day and my fuel air mixture was a bit lean. So I started jeting up. I didn't have two sets of every size so my carbs are different front and rear. I should also add that I was running the 94 octane pump gas that we get around here. It has some ethanol in it so it would require slightly larger jets anyways. Also my manifold is modified in a way that would be like an open carb spacer, that usually requires slightly more jetting too. Anyways,,, Here's what I ended up with on a pair of 500cfm Edelbrocks...
Front carb... Primarys... 389 jets with 6347 rods Secondarys... 400 jets

Rear carb... Primarys... 383 jets with 5749 rods Secondarys... 398 jets

When I left the line or shifted the fuel-air meter showed the engine ran a bit lean (about 13.5) for a second or so then level off at about 12.8. after installing the larger rear jets the fuel-air stayed much flatter and ran at about 12.5

By the way I'll bring the fuel-air meter with me to Clay City so if anybody's ambitious enough to weld a bung into one of the header collectors we can hook it up while you make a run down the track. Apparently the thread size is M18 x 1.5 :scratch It's suposed to be a comon size and easy to find at most parts stores. Here's one on line... http://www.innovatemotorsports.com/xcart/customer/home.php?cat=251

[MRHP]

Jim, what tire dia. and rear ratio you using. If I recall we have similar engines. I am looking to put in 4:56 gears for Clay City. Too low? I have a t 10 4 speed and 3:36 gears right now.

[jim_ss409]

I've got 4.11's and my tires are just a little over 26" tall so I was crossing the line at a little over 5,900rpm on my best run of 112mph. Here's a link to a really good calculator. http://www.race-cars.net/calculators/rpm_calculator.html It's interesting to see how much different tire sizes can affect your rpm.

[MRHP]

Thanks Jim. I'll have to do some more figuring. 4:11 just might have to work.

[MRHP]

If memory serves my jetting is 101 and 98 with 7047 rods.I have 8 inches of vac. at 800 rpm. 474 ci motor and 11.5 comp. Runs strong. Total timing 34 or 36. Can't remember for sure. Just barely runs on premium fuel.