This is my first post in carbs, I thought it might be of some inspiration to anyone seeking "more powah!"

When I first got my 82, after I wasted my time swapping to TPI, I was told that the computer controlled carburetor 305’s are 795 cfm's. Later I passed this item on to a guy I met at work. I helped him back when I lived in California to put a short rod 406 into an 83 or 84 LG4 Camaro (or whatever they called the computer controlled carburetor 305 then). He had bought a 400 replacement truck motor from a machine shop (short block) near by and didn’t realize what he was getting into smog wise until after the purchase. He didn’t know camaros were computer controlled, and lost interest in the project until he met me. It all started when he saw me each day nearby at work driving my old red 82. We got him some open chamber double humps with 1.94's. We put and Edelbrock replacement intake on it, it seemed to be made for an emissions computer car. He was concerned that when done it wouldn’t pass emissions. Remember this all took place in California. I was afraid the computer would go haywire. Back then there wasn’t much help for us computer guys cam wise, so we installed the crane 305 carb compucam (please don’t laugh). Well, we got him some exhaust and manifolds from a wrecked 89 TBI firebird. Are they better than TPI? I don’t know, but they are better than 84. The cat was a newer style and had fewer miles on it, the piping and manifolds looked like they were like TPI. We put everything back to normal on it, wires, sensors etc. we found a carb shop that rebuilt carbs, some cool old Mexican guy. Back then I had an old article for putting 350 HO GM crate motor into 305 cars, smog legal. It had the metering rod # and hanger # from GM to tune the computer Quadrajet for a 350 HO in the article. We talked to the old guy and he found a book that told part #'s for carb tuning parts and he told us the computer carbs are a little different tune than non computer carbs. Anyways we split the difference and found the perfect set of parts for the carb it passed emissions with flying colors. When we got done the car ran 12.90's at sears point! I bet it made around 290-300 rear wheel horsepower and 390-400 TQ which I think are good numbers for full smog. It ran 12.90’s even with no suspension parts, on radials, without sub frames. This all took place around 1992. I'm sure if there was much of an internet around back then, (not for me there wasnt) back when we drank, played super nintendo, and watched TV instead. I would have known even more stuff to do on this car but I think we did well with what we had. Funny thing is I don't remember if I ever found out for sure after all of that whether they were 795 CFM's or not.

 

nobody likes my story? or is it too old and lame? full of stuff everyone already knows?

 

I think it is a cool story.
I have a good time pissing around with my modified LG4 that still has the computer and emisions equipment.
When the 305 goes boom, I'm going to install a 350 with a larger cam than I have in the 305, higher compression, and maintain the emissions equipment. Who knows, by that time maybe I'll have enough money to replace these heads with a set of Scoggins-dickey modified Vortec heads.

 

P.S.
I've heard the cc carbs are 695 cfm.
I know the non cc Q-jets are 740 and 800 cfm.

 

I dont know exaxtly what cfm they are but they are around 650 in stock form, but this is just because there is a tab on the linkage that keeps the secondaries from opening all the way. If you grind this tab down I think you can get about 750 out of it. I dont know how fast I run but I have a 350 w/ computer controlled carb and comp cams xe268. I know that I raced a mid 90's LT1 z28 with headers, flowmaster catback, gears and hypertech reprogramming and ran dead even with him up to about 105. This was with my other carb on(still cc but I think I had the AV tension to loose and was getting a slight bog. I put on a rebuilt one a couple days ago. I think that the secondary tension is a bit to tight on this one but I am not getting a bog so it is better than the way the other was adjusted. Last night I raced a stock LS1 Z28 from a ~40 mph roll and ran even with him a couple times and beat him a couple. Mind you this is all with ported LG4 intake and heads. The heads actually still have the stock valves too. I have a set of sportsman II heads and performer rpm intake that I plan to start porting next weekend. Once I get them done I plan on swapping them on and hopefully wiping the floor with some LS1's. Still though I was pretty proud that I kept up with one on the high end where they shine with my current setup. I think that if I got a chance to race him from a stop I may have had him pretty good. Once I get the heads and intake done I plan to get the computer and chip for the 350 HO conversion that they made for these cars. I have a feeling that that will help out quite a bit because the lg4's stock timing curve blows. Anyway, cool story.

Ben

 

The way I remember it the stock 305 was more tolerant of timing therefore it had more timing programmed into it's chip and less programmed on the higher compression 350 HO's chip. The way I understand it GM was worried more abot too much advance effecting or creating excessive NOX's ( a smog gas) in the exhaust. So the 350 HO had less timing. I have no doubt that a person could make thier own chip the way that the EFI guys do. your prom goes right on, comes right off the computer. Unlike the late style EFI ones that come in a carrier. The sad part is that getting someone compitent to help you with something like this might be difficult. The chip is considered such old technology they might not want to "lower themselfs to that level". Or they may just suggest that you "EFI" it and "come see them afterwards". If you are serious about this you could probably read the same prom burning article from Traxion in the DIY prom section and learn to do it yourself. It seems like a lot of stuff to do to keep a carb. But considering the smog police state this country lives in its either that or just crank in some advance and call it good.

 

Trust me it doesnt have too much timing. I have around 10:1 compression because of the 58 cc 305 heads and have the timing at a base of 10 when 0 is stock and have ran around with the snap on scanner hooked up to it and dont get knock. I know that the lg4 which is what I started with had a lot less timing than the L69s also. Also, does the 350 ho have alum heads? It could have probably stood up to even more timing. I dont know, but if for some reason it does have less timing I may just order an aftermarket chip that is made for the LG4. I think hypertech makes them. I know that they say you dont usually gain much from aftermarket chips, but I believe I have quite a bit less agressive timing curve than I should or even what they "should" have put on the LG4's. I know that some of the people with 350's w/ cc quadrajets have said that car ran a bit smoother with the 350 ho chip. I think that they made 308 hp out of manifolds and a cat w/ 3" exhaust.

Ben

 

The old HO 350 conversion package used the ZZ4, which has aluminum heads and about 10:1 compression. But, they still had a decal in the kit to put on the dash that said "Premium fuel only". I'm running 10 degrees base timing on regular unleaded now, where 6 caused pinging with the stock LG4 and plugged-up EGR passages, even with mid-grade. Polished chambers and EGR do wonders for ping control.

There are two articles in the magazine section on this board by Steve Green with "Stroke in the Desert" in the title. He took an '83 'Bird, put in a 383 w/Edelbrock heads, cam, & exhaust, sent the carb & ECM to Jet for rebuild & new chip. He passed the Las Vegas smog testing (which is like CA & CO's) with flying colors.

Some day the bug is going to bite me, and something bigger is going into the Camaro. Haven't decided whether it will be a emissions-legal-looking 383, or after it's 25 years old and exempt from emissions (with 5 year tags), the 396 because the '57 gets a 502. Either way, the CC q-jet will probably stay there...

 

LOL, the 350 HO converion package was made when the motor that we call the ZZ1 was only called ZZ because it was the only one...

 

I have the page for it with the parts list and it says it uses the zz3.

Ben

 

Im sure any more recent article will have the later ZZ engines listed on it, Im just telling you when it forst came out when the kit was first introduced the first motor it was supposed to be used with was the ZZ or as we know it ZZ1. This kit is older than many of the members that frequent this site.

 

Hey, that's a pretty cool story. I like low-buck go-fast stuff. Having played with these Red-Headed-Step-Children carbs (computer controlled or not) for almost 2 decades I can appreciate when someone goes fast with one.

The CC-Qjet will indeed flow right up around 800 CFM if you get the secondary air valve open to a full 85-90*. They're all built off the QJet core that uses the large primary venturis (old 750 CFM units like were common in the early 70s used slightly smaller primary veturis).

The cool little secret about the CC-Qjet setups is that they are VERY forgiving of massive changes in displacement, cam, etc. The carb still acts like a carb and is about 80% self-tuning no matter what you slap it on (as all carbs are by their nature). The ECM really only does "fine tuning" for you. And only at idle and part throttle. Beyond that you're still in the world of old-school mechanical changes in calibration- jets, rods and stuff. Not at all like an EFI car that goes bonkers if you change some major operating parameters.

The LG-4 305 cars had a chip with a much milder spark advance curve. Original L-69 305 HO motor cars had a much more aggressive timing curve. I've made both go fast, but orignal L-69 calibartion it was easier to do.

 

I do a lot of driving on my job, sometimes as many as 300 miles one way to get to a job assignment.
My 1988 Silverado 4x4 isn't cutting it in the mileage area, with 14-16mpg average.
Way back in the late '80's, I had a 1981 Caprice that got 21-22mpg on the highway, even with over 200K miles on it. When the engine went bad on it, I parked it as finances wouldn't allow me to do what was needed to keep it on the road.
Remembering that car, and how comfortable it was, and the decent mileage it got, when I saw this old Impala sitting behind a shop last month, I had to check it out.
Yep, it was for sale, the body was straight, paint was faded some, interior perfect, under the hood everything looked factory, no butchered wiring or other things to have to sort out.
The owner said it had a burnt valve. Turn the key and fire it up, and yes, it had a miss. Other than the engine and it's miss causing the car to rock back and forth, you could not tell it was running. It was super quiet.
Two-hundred fifty dollars later, I am driving this thing home.
Transmissions shifts ok, door seals need replacing, brakes work good; I got a good deal, especially for what I have planned.
I remembered that Chevrolet had offered the ZZx conversion package for Camaros with the LG4 engine back in the 1990's. A quick web search gave me all the part numbers (I was too lazy to go digging through my old CHP magazines to find the writeup) used in the kit.
I especially wanted to know what secondary metering rods were used, and the Corvette servo and other tranny parts used as the Impala has a TH-700R4 rather than the TH-200-4R.
In my shop I have a pristine 1997 Vortec 350 long block, with 15K miles on it.
I am thinking of installing an LT1 cam later, but for right now, I want to see what the old car can do both performance wise and mileage wise with the stock Vortec engine with an Edelbrock intake and the CCC Quadrajet on it.
Someone mentioned the PROM from an L69 car......I have several ECM's from '85-88 Monte Carlo SS's stored away. I am not sure on the interchangability of the PROM's, so that is one area of possibility I have to explore.
As to the paint, well, I've already prepped the body, and in the continued interest of low-bucking this ride, I'm sending it to the local Maaco shop for a new coat of factory Midnight Blue Metallic just like it came from the factory with in 1983.
I don't want or need a show car, what I want is reliability and mileage, with some performance potential thrown in when I feel the need to mash the GO pedal.
Too many folks jump on the "EFI it" bandwagon.
FWIW, I like EFI, but I know from firsthand experience that carb'd cars can be fun to drive, and are a heck of a lot less hard to sort out when you start tuning them.

 

The first ZZx crate motor was called the ZZZ. When it evolved from the ZZ2 to ZZ3, they changed to a shorter intake and smog legal cam so that it could be swapped into a third gen Camaro.

 

Wow! thats right! I forgot all about that stuff. So I guess the zz2 would have been the first motor it was sold with. Not the zzz (zz1) I thought it was earlier.