So it seems that Carter AFB/Edelbrock Performer carbs are notorious for having the problem of stumbling while on the gas going through hard turns.
What can be done to remedy this problem? Get a high performance fuel pump and put a regulator on it???? Or should I just say screw it and get a Demon? I spent a good while rebuilding and polishing a Carter AFB that I got a screaming deal on, and was planning on running that.
I like the streetability of those carbs, seems alongside the Q-jet as the best street carb to run. But I am building this thing up with canyon carving G-machine action in mind, or at least some spirited road driving and maybe SCCA Solo II.

HELP!

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'71 RS/SS project: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / big 4 whl discs, 1-5/16 VSE ft & 1" Rancho adj. rr sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

I know they make an "offroad" needle and seat setup, as mine came off of a truck and has the spring loaded "offraod" needle and seat. Or at least it did until I put a new set in with the rebuild parts. Is this problem related to the need to have a spring loaded needle and seat for offroad truck use like that?

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'71 RS/SS project: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / big 4 whl discs, 1-5/16 VSE ft & 1" Rancho adj. rr sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

your right, the spring loaded needle & seat are basically just a off-road 4x4 part. At extreme angles it is (supposedly) possible for the needle to pop back up due to that pesky gravity thing http://www.nastyz28.com/ubb/wink.gif

I've been messing with Edelbrocks for a few years now since getting fed up with Holleys & I just wanted to prove they could run with a Holley if prepped right. The larger needle & seat (.101 I believe) wont help this problem. I had to use the large needle/seat combo to cure a high rpm fuel starvation problem. Your deal is the float setting. I'd go back & double check it both ways-the "drop" & the "seated" setting. If this doesnt cure it, then you could actually make it a dual feed Edelbrock. Some guys have been doing this for a while, thats why Edelbrock made the new Thunder carbs dual feed. The top of the carb has the boss for the other fuel inlet & its actually a very simple modification. But....as much as I hate to say it, I dont think this is the best carb for road course type racing since this is the weakest/most annoying part of the carb! I'd go with a small Holley/Demon type for that.

I'm sure youve heard it before, but 6.5psi is the sweet spot on these carbs.

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11.74/118mph, thats all..

I had a 600 manual choke on a 350 in a blazer. The offroad needle and seat kit was a great addition for the rocky up and down climate I abused thid truck in. It is kinda lick a shock absorber for the float system. I also took a peice of fuel line and cut it to size to sorta plug the crossover at the rear of the carb, this way each float had to control its own side, so to speak. This worked good for me at off camber climbs. The carb never hesitated. I've been building hi out put motors for a long time, and never mastered the holley carb, so I gave up, had good luck with the carter/weber/ edlebrock. I did a search on offroad mods to the eddy and a dude has a site with a v-8 land cruiser, learned alot from the read. Don't have a link hope this helps

stumbling/stalling in hard turns or under hard breaking is float level adjustment off.

Set at rest level on both to 7/16" and set drop on both to 15/`6" to 1"

The other common prob is bog when romping down on the throttle.. This most of the times is the pump arm likeage. Move it to top hole.

The last common prob with these carbs is how they are picky to fuel psi.. under 5 psi and they run like junk, or over 5.5 psi and they flood and run like junk.

I set mine to 5.25 psi

So I should definitely get a fuel pressure regulator and run it with these carbs? I was going to go with a Carter Super Street Mechanical fuel pump, it delivers 6psi I believe.

How exactly does one go about making an AFB/Performer a dual feed? How do you tap the threads in the carb? The hole doesn't go all the way through, does it? I'll have to pull mine out and look at it.

I guess I'll run it for now, and if the problem occurs and I cannot remedy it, maybe I'll get a Demon or a Street Avenger. I got the float adjustments dead nut when I rebuilt it, but I haven't even put the engine together yet, and the car won't be running again for a while.

Any other suggestions?

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'71 RS/SS project: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / big 4 whl discs, 1-5/16 VSE ft & 1" Rancho adj. rr sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

Alrighty, I was thinking a while today at work... If I want to use my dual snorkel cowl induction air cleaner ('vette base with 80Z28 mating ring/lid/seal/air induction scoop), I know a Holley won't work without a spacer because the float adjustment screws hit the air cleaner base big time. The Carter AFB will clear with a little hammer work and a banjo fuel fitting. These air cleaners were made for Quadrajets, which seem to perform great when tweaked, and also seem to be neck-to-neck with the AFB/Performer carbs as far as best street carb.

Now, my question is, it seems that most aftermarket manifolds are all for squarebore carbs? I have seen the suarebore to spreadbore adapters that are maybe a 3/4" thick carb spacer. I don't have this room to work with however. I have a Professional PRoducts crosswind airgap intake, like a performer rpm airgap only a little shorter. I am switching back to standard solid body mounts vs 1/2" drop due to air cleaner height and raised exhaust ports on E-Tec and Vortec heads, for header to floor clearance.

Now, what intakes can I use that are of the rpm airgap style that can use a Quadrajet? Or can I just hog out the top of my intake manifold with a die grinder to make it look like the inside of a squarebore to spreadbore adapter? I'll have to look and see if this is an option, can't remember if my intake has multiple carb bolt patterns. I think it may, but I'll have to look. Maybe it could be tapped anyhow?

What are the options here? I'll probably run the AFB initially, as it was pretty new when I got it, and I rebuilt it, but if I encounter stumbling problems on hard corners, I will maybe try and reset the floats a little higher than the suggested adjustment, and if that doesn't do it, I'll do the sensible thing that I should have done in the first place and get a Quadrajet.

Whatever happened to that web page with all the great Quadrajet tuning tricks? Listed GM part numbers of super cheap stuff to get to modify them. Link didn't work last time I tried it.

How thick are the adapters, anyhow? I'll be using 70 Z28 engine mounts to drop the block down a bit, but I don't think I'll have much room! I'm using a Buick trunk weatherstrip as the seal, it's thinner than the stock 80Z28 air cleaner rubber seal. I even thought about modifying the air cleaner and cutting the rest of the hood out under the air induction scoop so that the air cleaner could sit up in the scoop a hair. This might be my best bet, to trim down the top of the air cleaner so that the seal sits lower on it, for more hood clearance, and relocate the snorkels a little lower with some very tedious sheetmetal sculpting, since the snorkel tops are so close to the top of the air cleaner already. I guess I'll cut out the hood regardless, just so, with the scoop off, I can close the hood and measure how much clearance I have so I know what I'm working with. MIG's really come in handy for this kind of stuff...

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'71 RS/SS project: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / big 4 whl discs, 1-5/16 VSE ft & 1" Rancho adj. rr sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

[This message has been edited by Chuck78 (edited May 19, 2005).]

Looking at some adapters, it looks like the Quadrajet spreadbore style carbs use the closer bolt pattern, so ssince my intake is for squarebore carbs, I could always just drill and tap the holes further in for the spreadbores.
http://www.sevensaturdays.com/auction/parts/sbo/spreadbore1.jpg
Looking at the adapters again, it looks like the standard squarebore style would have as much meat left on it after the die grinder treatment as the adapters do, so the seal of the gasket would still be about the same.

Has anyone ever done this, or is this unheard of? I am thinking that if I have this stumbling problem in corners, that I will want to switch to a Quadrajet for sure, but I don';t want to lose the vortec style airgap intake... Professional Products also makes vortec performer knock off intakes in the spreadbore style, but no rpm airgap style spreadbore. I'll have to get a gasket from my dad for spreadbore carbs and hold it up to my intake to see if it could really be done.

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'71 RS/SS project: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / big 4 whl discs, 1-5/16 VSE ft & 1" Rancho adj. rr sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction

Chuck, it sounds like you haven't tried running the car yet. I have had good luck running a 750 Edelbrock on my car while auto crossing for the last 4 years. I think you should try testing the car in its current configuration before making any further changes. No point in fixing what isn't broken. I also use an Edlebrock pump and I do run a fuel pressure regulater set to 5.5 psi.

The only car with a carb I have ever seen having problems autoXing was a newer mustang someone converted to a holley. Every corner the car would die, I suspect the floats were set to low.

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1980 Money Pit deeper and deeper it goes
http://www.frontiernet.net/~bullockcm/1980camaro.html

Yeah, I was just thinking ahead in case I do run into these problems. Looks like I could most likely convert my intake to a spreadbore with a little die grinder work. Might need to tack a quick bead with a tig around where I'd be drilling the quadrajet mounting holes, as it'd be right on the edge of the pad at the back two bolts. Easily do-able if I really wanted to. I do intend to run the AFB first, however.
If I have an Carter Competition Series AFB 750cfm (Weber makes these for Carter and Edelbrock), and a Carter Super Street Mechanical fuel pump, is there going to be a need for a regulator? What kind of symptoms am I going to see if I have too much pressure? The pump says it puts out 6 psi, I believe.

Now I'm looking at the Edelbrock Performer fuel pump, which looks a little nicer, and has 3/8" fittings vs the carter's 1/4". Both say they produce 6psi. I am leaning towards the Edelbrock, but not sure.

Can both of these pumps be used with a vapor return line, or should I just do away with the return line?

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'71 RS/SS project: full roller 406sbc / 9.76:1 w/ E-Tec Al. heads / 750 Competition AFB / big 4 whl discs, 1-5/16 VSE ft & 1" Rancho adj. rr sway bars / 4 speed 3.23 posi / 81 Z28 & dual snorkel vette Air Induction