I recently let a shop swap out my intake and carb from the factory intake and quadra jet to a edelbrock preformer intake and 9906 carb. During this process they removed all the pollution garb and did a dual exhaust. I wish I had just demanded them to rebuild the quadra and leave it along. If I am going along in second gear and holding say 2k rpm the car lunges. I have talked to a few people and they say I got a bad re manufactured carb. Well before I go raising cain with these people and being with out my car again for a week I thought I would ask if any of you could lend a word of advice.

They have tweaked at it for a week and still a lunge

 

What distributor did it have when you got it back?

I have yet to be convinced that anyone has "upgraded" by replacing the factory q-jet with an aftermarket carb, at least for a daily driver car.

 

Same stock Dist. that it left my place with. I understand what you are saying about replacing the Qjet but you will have to understand that in 10 different applications I have yet to find what others refer to as a good Qjet. I have and always will call them a Quadra Junk. Never have I had one what was right. I just want the car to be right for a fun driver. Not an everyday car just a hey kid lets go mess with the little boys up town in thier daddys cars.

 

There are at least as many Edelbrock threads in this forum than q-jet or Holley threads. That should tell you something, especially since our cars never came with Edelbrock carbs.

In spite of what the Edelbrock tech line may have told you, until you get a vacuum/mechanical advance distributor installed to go along with the Edelbrock carb, you will never get it to run correctly.

Calling a quadrajet "quadra junk" is ignorance. That's not an insult, it's a call to educate yourself (ignorance is a lack of education - stupidity is the inability to be educated). The factory computer quadrajet is the best possible street performance carb available, regardless of factory or aftermarket. If yours wasn't operating correctly, most likely it was "worked on" by someone who didn't know what they were doing. I had a rebuilt one on Berlinetta #2 when I bought the car - carb looked great, car wouldn't start or run worth a hoot when cold, and wasn't all that great when warmed up. I found out the choke had been tied open and many settings were improper - on a freshly rebuilt carb! I untied the choke, set everything to factory specs, and the car started and ran like new (and passed the strict Colorado dyno sniffer emissions test with ease), even though it had 300k miles on it.

Stupidity would be not to educate yourself. That Edelbrock will never run as well as the q-jet could. Never.

 

Five7 maybe you missed the part where it said I should have demanded them rebuilding the Qjet. The Qudra Junk comment is only of personal experience with the things. I have been told many many time that the Qjet if it is right is the best there is but when they are not correct well thats another story. I dont think there is anyone in Ohio that I have heard of that can get one to be "when its right" Educated I am, stupid I am not. Willing to do what ever the car needs is what I will do to have a nice running car. Now a 3rd Gen guru I am not but it seems to me I seen a vac advance on this car. Again I could be totally wrong because I have been under the hood of alot in the past few months tinkering with buddies. I chose to have this done professionally... I use it loose ok..... because I wanted a nice neat job done and I do not have all the vac gauges and timing light tools at my finger tips.

 

five7, good call on the vac ad advance, ordering tomorrow

 

I saw the title to your thread, and I just had to check it out because lunging was the L69's biggest and most common problem when it was new.

I don't know if this applies to the '84 HO engine, but the '83s had a "hot fuel pick-up" problem, and the engine would lunge during low-speed acceleration. One of GM's "fixes" was to install an in-tank pump, which helped, but it didn't solve the problem completely.

IIRC, the fuel line in the engine bay was too close to the exhaust manifold, so the fuel would "boil," causing a vapor locking sensation, and the car lunged like you were riding a bucking bronco. It was like you were popping the clutch over-and-over, or tapping on-and-off the gas pedal.

Another GM "fix" was to try to shield/insulate the fuel line from the exhaust manifold, but I don't think that solved the problem completely either. That one might even have included a tiny fan... really lol. The '83 L69 I had never got that fan kit, but I've seen pictures of it.

Given that you had the entire intake changed and a full exhaust installed, maybe the solutions GM developed to try to solve the original problem got deleted or changed. So before you start having things torn apart and spending a lot of money on hopeful fix-it parts, you might look into that.

 

LA,
I am fairly convinced that this is not the case in my car. I went home last night and set the carb per the Edelbrock tech's recommended starting point and the car ran better right off the bat. making 1/16 turns on each screw while out driving the car I got it dialed in to where I am VERY VERY happy with the car except upon restart while she is at operating Temp. Maybe this is where the Vac advance comes in that 57Kid was talking about. I am starting a new post so it will gather the attention of some that may be able to point me in the right direction for this. I would bet good money that putting the advance distrib in will finally solve my problems. 57 and I for sure have different opinions on Carbs but I think he sure hit the nail on the head about this.

 

That's exactly when the car would do this: upon restart when the engine was already hot.

But you guys are probably right... just thought I'd throw that out there.

 

LA.
My problem did lay with timing and vapor lock. used some steel tubing to re route fuel line as steel will dissipate the heat far better than rubber hose and installed a new mechanical/vac advance dissy from MSD. The car came back to life putting a smile on my face for hours. This is the car I tend to enjoy this summer not that lunging thing that I hated a week ago.

 

Whats funny is that 9906 edelbrock carb is 600 cfm while the 305 HO has a 500 cfm q-jet along with a special intake manifold.

I see no advantage....................

 

No, it has a 750 CFM q-jet.

 

GEE.............I guess we are both wrong.

From 2 notes at camarosource.ca:
On the mechanical side, Cross-Fire injection was dropped, but the Z28 offered an optional 5.0-liter 190-hp H.O. (650-cfm) V8 engine......
The L69 H.O. V8 came with a 650-cfm quadrajet 4-bbl carburetor.

Plus other goodies noted at TGO:
The H.O. engine came with a higher lift and longer duration cam, dual snorkel intake system with a "5.0 Liter H.O." decal on the air cleaner, specially calibrated Quadrajet carburetor, lightweight flywheel, electric cooling fan, bigger 2.75 inch exhaust, Corvette style wide mouth monolithic catalytic converter, 5.0 Liter H.O. exterior/interior identification, and came standard with a 3.73 rear axle gear.


I guess the OP LOST some cfms on his more power swap eh?

 

No, only you were wrong before. And now we can add camarosource.ca to those who are wrong.

 

Yawn................

From another forum:
The difference was Chevrolet with the L69 replaced the LU5's induction system with a performance tweaked computer controlled Rochester Quadrajet (650 cfm) 4-bbl and an aluminum intake manifold. The L69 had the LU5's 9.5:1 compression ratio which was much higher than the LG4 4-bbl 305's 8.6:1
http://www.oldcarmemories.com/content/view/104/1/

Another:
The L69 H.O. V8 came with a 650-cfm quadrajet 4-bbl carburetor and could ONLY come with a 5-speed. There was NO L69 available if you ordered an automatic transmission, in which case you could order the TPI version of the L69 (LB9 190-hp 5.0-liter TPI V8). The LB9 engine required an automatic transmission.

 

five seven is right, there is no such thing as a 650 quadrajet. There is only one quadrajet and it is a 750. Also I am doubtful about the statement that the L69 didn't come with an auto.

Cheers

 

Can't argue with you there...

Go ahead and quote as many of the uninformed as you like. It won't change reality.

(FWIW, in the early days, some big blocks got 850 CFM q-jets. But, the CC q-jets were all capable of flowing 750 CFM - some had a tab that restricted the air valves from opening fully, that limited their flow; but, those were all on LG4's, not L69's. Check out the q-jet tech article for more info about how to make it capable of full flow.)

 

Q-jets were made in two sizes one with 1-3/32-in venturi (primary) 750 cfm, and the other 1-7/32-in venturi (primary) 800 cfm. and as mentioned the 750s were tuned to 590 cfm by allowing the air valve to open about 50 degrees, as well by limiting the secondary throttle blade angle.

 

True there was also 800 cfm q-jets on certain big block buicks, olds, chevys
but the several quotes and links I posted mentioned the 305 HOs had 650s
so who REALLY knows?????????

I suppose I should eyeball the numbers off my 84 HOs q-jet and cross reference
it with the q-jet reference books on line to REALLY know for sure............
The few I have seen show different carb #s for the 150hp and 190 HOs and
again different #s for the big blocks

NOTE: COsmic.... the reference above for the HO only with the 5 speed was from a 1983 GM brochure. Not avail with the auto till 84.

 

OH OK, I have an 84 L69 Auto, that would explain things a bit.