Upgraded intake, cannot get carb in tune

[Bluemonster71RT]

Hello peoples. I haven't had to post in a while as things were going ok with the car. Until now. I upgraded to a Edelbrock Performer RPM from a Performer. The car ran pretty good with the first intake. I figured on only minor adjustments. Seems that it is not the case. With just swapping the intake, initially I had to readjust the idle air screws and that seemed to be ok. When I took it for a ride it was going lean towards the top end 15-17 on the meter @ about 3500-4000rpms. So I up jetted. Nothing changed. So I checked my vacuum and it seemed to gain from 11 to 12.5. So I changed the power valve from 5.5 to the stock 6.5. That seemed to fix the issue but then I would get massive rich condition when trying to go from a stop with normal acceleration. Full peg, rich, bog and all. It would clear up after getting the rpms up. I cannot get rid of it now. Ive changed back to the 5.5 PV. Swapped jets down a lot. Still goes rich but then cruise is too lean. Put a squirter 3 sizes smaller on and still same problem. Idle is great. Throttle response at idle is great. Seems to be ok after I get out of that rich spot but its too rich to risk driving. I even put the Edelbrock 750 I had on and that was just a mess of lean and rich all over the place performance that I am not going to bother with that. What would cause the car from being so rich at tip in that I can't tune it out?

383 edelbrock heads
Avenger 770
RPM intake
Unsure of the cam.
Idle 950-1000
11-11.5 vac
MSD 6AL and MSD distributor timing ini 18-20 depending on fuel
Holley mechanical fuel pump
   

[gzig5]

I'd start by looking for vacuum leaks around the intake and carb.  Spray starting fluid around the carb base, throttle plate shaft, and both head to intake junctions with it warmed up and idlign.  If engine speed increases, you have a leak.  The intake change shouldn't have generated such a radical tune change.

[Chryco Psycho]

NOt sure exactly which carb you are working with but if it goes rich opening the throttle you need less accelerator pump , so smaller squirter & or diff cam with less volume Pink cams have a large deliver volume , white & blue are much better 

[70 Challenger Lover]

Cody posted this a while back. I found it so useful that I saved it for reference.

[Bluemonster71RT]

Street Avenger 770 is the carb. I went from a 31 on the squirt nozzle to a 25 and has the same issue. I was thinking maybe a vacuum leak but using the gauge to do idle, it doesn't reflect that there is one. Ill check anyway. I am using the green cam. I was in the #2 spot prior and switched it to #1 to see if it changed but nope. I can swap to others but I think my problem is something else.

Since my last post I did take the carb off again to check the transfer slot. I set it correctly and fired it up. No matter what I cannot get it to idle good at anything under 950rpm. At 950rpm and up though, the i/a screws have little to no effect. And on that note, the car will not restart if it is set to max vacuum and 950 or less rpm. I have to re-crank the idle speed screw in 1 1/2 turns to get it to re-fire. This is boggling my mind. So either I do have a vacuum leak somewhere or this carb oddly went out to left field randomly.     

[Chryco Psycho]

Air bleeds
Take a piece of welding wire .035 bend it so it has 2 -90* bends & drop it into the outside bleeds front & back , it will clean right up
unfortunately with that carb you cannot change the bleeds but you can pinch the wire behind the squirter

[Chryco Psycho]

Did you see this @Bluemonster71RT ?

[Bluemonster71RT]

Did you see this @Bluemonster71RT ?

Yes! Sorry haven't had a chance to get on.  So a few things were prompted from the idea of dropping a wire into the air bleeds. 1 is I put wires in as suggested and the second is I ordered a new carb just in case. I will not get a chance to fire it up until this weekend. I have been getting home too late to make that much noise.(poor neighbors). So if the wire works then I suppose a new type of carb would help. If they don't, then probably both carb problem or something else is wrong at the cause of swapping the intake. I have ruled out a vacuum leak as it would give me a lean condition I believe. So I guess we'll find out Saturday morning. Also I'm going to tear down the Avenger 770 again before I bout up the new carb in case I find something I missed maybe 

[Chryco Psycho]

The wire will help I have done this many times now

[Bluemonster71RT]

Do you just leave the wires in there or do you usually save for a new carb that has adjustable air bleeds?
Either way I ordered this one. https://www.summitracing.com/parts/QFT-BR-67302 Half based of a few of your posts on a bunch of forms. Though you were more partial to the Holley HP version on more than a few posts.  It's amazing how many times you show up from various places on questions I ask google. 

[Chryco Psycho]

I have left the wires in place usually pinched behind the squirter
My Fav is Proform / bang for the buck , QFT & Holley HP are good as well !
I guess I have been doing this for a few decades now going back to 76 or so

[DeathProofCuda]

Do you just leave the wires in there or do you usually save for a new carb that has adjustable air bleeds?
Either way I ordered this one. https://www.summitracing.com/parts/QFT-BR-67302 Half based of a few of your posts on a bunch of forms. Though you were more partial to the Holley HP version on more than a few posts.  It's amazing how many times you show up from various places on questions I ask google. 

What is the difference between the Brawler Street and Race models.  Does the Street model not provide the adjustable air bleeds?

[Chryco Psycho]

I would have to check But usually both would have replaceable bleeds but street series would have a choke

[Brads70]

Do you just leave the wires in there or do you usually save for a new carb that has adjustable air bleeds?
Either way I ordered this one. https://www.summitracing.com/parts/QFT-BR-67302 Half based of a few of your posts on a bunch of forms. Though you were more partial to the Holley HP version on more than a few posts.  It's amazing how many times you show up from various places on questions I ask google. 

What is the difference between the Brawler Street and Race models.  Does the Street model not provide the adjustable air bleeds?

They both have adjustable air bleeds. I notice the linkage is different than the one I have? This has Annular boosters,  but other than that and the finishes....? Should be a great carb for you!
This is the one I have , can't believe how much it has gone up in price! Before I'd spend that I'd have a long hard look at fuel injection. They are going to price themselves into extinction if they keep going.
https://www.summitracing.com/int/parts/qft-q-850-an/overview/

[dodj]

Do you just leave the wires in there or do you usually save for a new carb that has adjustable air bleeds?
Either way I ordered this one. https://www.summitracing.com/parts/QFT-BR-67302 Half based of a few of your posts on a bunch of forms. Though you were more partial to the Holley HP version on more than a few posts.  It's amazing how many times you show up from various places on questions I ask google. 

What is the difference between the Brawler Street and Race models.  Does the Street model not provide the adjustable air bleeds?

My QF street series has replaceable air bleeds, idle feed restrictions,
As well as not having a choke horn, I believe the race series are really optimized for WOT. Other than before the start of a race, a race car lives at WOT pretty much all the time. A street car is rarely at WOT for any length of time.