Suggestion/experience, Need a new Carb
 

Happy Independence day!
Ok gentleman, I need a new carb that I can get to pass emissions, I currently have a Holley 9895 (I thought it was a 80555C, came in an 80555C box, no numbers on the body/plate except list-4175) took it too a reputable shop here in town to help me tune it because I got a whooping 6 mpg out of this last tank. The 9895 has a reverse idle circuit, so what I thought was full lean was actually full rich. Shop guys were pretty unanimous about ditching the 9895 as they are apparently really hard to get to run efficiently/correctly and I was told a not very good for towing anything more than a roller skate. So I'd like your experience(s) and suggestions? I do have the original quadrajet but it is seized solid and un rebuildable. I've got an Edelbrock 1407 that came on the truck when I got it, but I've been looking at a little larger CFM 650 or so. I currently have a a stock 350+TH350 +NP205 (also an Edelbrock 2104 intake) and running 4.10s...I'd like better than 6 mpg and still like to tow. I don't expect great mpg... But 6 is way too low. And on top of all of that still need to pass emissions, even if I have to retune after passing. Edelbrock AVS2 1906, Edelbrock 1904? Holley 650 brawler? Holley Avenger 670? Holley 1850? Thank you everyone you guys have been a fountain of knowledge.

Re: Suggestion/experience, Need a new Carb
 

I have the AVS2 and like it a lot better than the Quick Fuel carb it replaced. The Edelbrock
is more driveable and mileage is def better. I did install an AEM Air/Fuel Ratio gauge as it makes tuning a lot easier than trying to read plugs etc.
Happy Independence Day.....America!!

Re: Suggestion/experience, Need a new Carb
 

Historically, the Quadrajunk was your best bet for emissions and maybe mileage, but the Edelbrick AVS2 has really good atomization, so should be able to run clean and efficient

Obviously, blowby and bad timing can make any engine run dirty

Re: Suggestion/experience, Need a new Carb
 

Timing is 32 degrees advanced all in(total timing) at about 2900(ish) rpm and the truck runs magnificently on the highway, even at 60mph, but 6 mpg is WAY too low. The engine has less than 200 miles on it since the new crate motor was put in and spark plugs look a little darker than the usual brown, But not black, so I don't think that blow-by is an issue but I will investigate further. Oh and my vacuum is about 18 Hg at idle (750 rpm)... But it does "bounce" about 1(ish) point at idle unless it is full rich, where it then sits at about 22 Hg with zero bounce.

Re: Suggestion/experience, Need a new Carb
 

Does Arizona not require original equipment emissions controls?

Re: Suggestion/experience, Need a new Carb
 

Diesels/ heavy trucks = yes, others just have to pass emissions "standards". NOX/CO2, Carbon monoxide etc. But I'm not 100% on that, it just what I've seen/been told.

Re: Suggestion/experience, Need a new Carb
 

For what year truck?

Re: Suggestion/experience, Need a new Carb
 

It is a 1971 GMC K2500 4X4B Body/chassis, but has a 1993 spec stock 350 (L44 RPO) with swirl heads and a 2104 Edelbrock performer intake.

Re: Suggestion/experience, Need a new Carb
 

Emission standards are tougher in Maricopa than in Pima County.
I got around having to get the 350 in my '71 GMC K/1500 Jimmy tested every year by getting Year-Of-Manufacture AZ plates ['69-'73] and classic car insurance thru Hagerty. Now I can avoid ADEQ.
I just switched my '68 C/10 Stepside insurance to Hagerty, too. Still has dark red late '80s commercial plates, but I'll have to change in October when registration's up. A perq of the old Commercial plates was the privilege of parking in a Yellow Zone 15 minutes with flashers on Downtown. I'll lose that, but it's not important.

As for Carbs -- I ran a Holley for 25 years on the 292 L6 in my Stepside. When the engine got rebuilt in 2005, the Holley R8007/4160/ 390 CFM [also re-carbed] lasted 500 miles thru break-in, then went nuts. Wouldn't hold a tune. Suspected a warped base plate. It was cheaper to get an Edelbrock 1404 AFB clone. Haven't looked back. Great carb and more power.
:chevy:

Re: Suggestion/experience, Need a new Carb
 

I've got Haggerty and "classic" plates currently, but if I want to use the truck for work I need to pass emissions. I haven't found a 1404 or 1904 (what Rod's Carburetor suggested) I have found a few old Carter's but man they look wrecked and people want a premium for sure.

Re: Suggestion/experience, Need a new Carb
 

I used my Jimmy for work and never needed emissions again. I looked all thru that policy
but never read any restrictions on usage or mileage.
Not like they're going to check anyway.

Re: Suggestion/experience, Need a new Carb
 

MVD told me point blank when I titled and reg my truck 5k or less miles and I'd need commercial insurance if over 5k miles *shrugs* I haven't personally looked yet

Re: Suggestion/experience, Need a new Carb
 

I have a 1405 on my '71 Jimmy w/ V8 350. 600 CFM.
Actually, it's a Federal Mogul Carter AFB 9605S, but if you tell the Edelbrock tech reps it's a Carter, they clam up. Same carb. Made in same plant by Weber.

With a .030 overbore, the 292 is really at 296 CI. 500 CFM is good for that L6.

Re: Suggestion/experience, Need a new Carb
 

ADOT/MVD is a lot meaner in Phoenix. In Pima County, they only ever hooked up the sniffer probes to my dual exhaust pipes. Sometimes only one.
I tried to run thru ADEQ in Chandler in 2006, and they started to hook up something under my hood. I aborted the test and tried again in Tucson.
Some 'smart' mechanic said I was getting a miss because the Brake Booster was getting vacuum from the plenum of No 6 of 5 cylinder, and that was giving me a misfire. So I had no power brakes for the run down to the ADEQ facility. White knuckle run. But it passed.

I used to keep a set of leaner jets and metering rods to put in the carb on the 292 before running in to test. Once passed, we put the fatter jets and rods back. But I found it ran fine on my ''Emissions Set'' year round, so I kept them in. And I've passed emissions for the last 4 years. But it's an L6.

Never heard of Commercial Insurance.

Re: Suggestion/experience, Need a new Carb
 

So... Because this truck has a flatbed USAA will not insure it, end of story. The do either partner with or have a separate division of some sort that deals with commercial vehicles and that is what they consider this truck to be. Well to be able to drive it more than 5k a year it has to go through emissions and needs commercial insurance for me to be able to use it for work purposes according to 2 different "sources" at 2 different MVD locations... It is convoluted Bureaucracy at its finest. Right now I have it insured with Haggerty but it says in my policy if I get in an accident while the vehicle is being used for anything other than personal/pleasure or exceed "x" milage they can chose to deny my claim or anyone injured by the accident and I can/will personally be liable... And I'd rather not find out.

Re: Suggestion/experience, Need a new Carb
 

Where do you hook up the A/F mixture gauge? I get it kinda works like an regular O2 sensor (kinda) but I've never personally seem one on our style truck unless the LS swapped it.

Re: Suggestion/experience, Need a new Carb
 

OK. Extenuating circumstances I was unaware of. I got into a bumper lockup at work with my Jimmy and a fellow worker's later vintage Ford pickup. My bumper was steel, his was plastic. I had no damage, but tore that plastic bumper up. I didn't hide that I drove it to work. They didn't seem to care.
But I guess there's a difference if you're working the truck as opposed to getting to work in the truck.

Re: Suggestion/experience, Need a new Carb
 

Correct, I'm trying to use the truck as a livery service for live stock or possibly a haul-away and recycling service (or both). I'd rather be above board on the "front end" than end up losing on the "back end" so to speak.

Re: Suggestion/experience, Need a new Carb
 

from my understanding years ago concerning emissions....if you put a newer engine in your truck, technically the standards change to the newer engine....however, the VIN tells them what engine it originally had and they go by those standards....unless you tell them its a 1993 truck engine, etc. Being that your truck is a '71 3/4 4x4, I dont think emissions would be too tough, but still sucks. I would imagine you can use a Holley 670cfm, lean out the idle screws, go thru emissions, then adjust them back to where you want after you pass.....OR different carb to go thru the test that is leaned out with leaner jets and just use that to go thru emissions.....OR change jets each time, OR.....the games we gotta play for Maricopa emssions.... :(

Re: Suggestion/experience, Need a new Carb
 

you sir, are speaking my language. I'm not about to tell them that it's got a new engine in it. But yes I believe that 71 standards are lower. The question I'm trying to figure out here is is what everyone's suggestion is/ are. If a holly Avenger 670 will work and I just lean the tar out of it then I'm going to run with that, I have no loyalties to brand. If I can get an Edelbrock avs2 to work fine.. then I'll run with that. Again not to worry about brand just worried about passing emissions and getting better than 6 Mi to the gallon.

Re: Suggestion/experience, Need a new Carb
 

I'm another "yes" on the Edelbrock AVS2 with its annular primaries. Better cold starts and easy to tune if you're looking to optimize MPG.

https://www.motortrend.com/how-to/19...vs2-carburetor

Re: Suggestion/experience, Need a new Carb
 

I did one couple years ago. You weld a bung into the exhaust pipe 6 to 12 inches from collector. You want it close so temp is still fairly high but not too close as to get a poor mix from the 4 ports. Wiring is simple. Exhaust leak are death to the reading. You got to have a very tight system to the sensor.

Re: Suggestion/experience, Need a new Carb
 

This at least used to be true. I was a smog tech until '84, when I went to work as an engineer. Replacing an engine with a newer one did require using that newer engine's emission requirements. Putting in an older engine, one still had to bring the engine up to the YoM requirements. Here in California, '75 and older vehicles are emissions testing exempt, but are supposed to have the factory-installed emissions equipment. But since they aren't testing them, people get away with a lot. That was the reason for my question- if a vehicle is still required to pass an emissions test, I'd expect that the equipment would be present (and operating). So, different states, different takes.

Re: Suggestion/experience, Need a new Carb
 

Like Pbfut said you weld in the bung and route to the gauge. I mounted my gauge in the original cluster in an unused hole.
I can get a pic if you want but its on the lower passenger side of the cluster.

Re: Suggestion/experience, Need a new Carb
 

It's my opinion that using a carburetor that was actually engineered to pass emissions will help. Qjets would be my first choice for your situation. I have very little experience with the AVS Edelbrock's but they seem to be an improvement over the rest of their stuff.

To do this you're going to need to find someone who is experienced and has the jets and parts to set up your carburetor. The next step is getting a accurate emissions test. This can be done at many shops but, they need to have maintained and properly calibrate their equipment to give you an accurate test. Most states have equipment that is far more accurate than what your average shop has.

Here in Oregon it's $25 bucks for the first test and the rest are free. So many shops will get a baseline on there equipment then run it through the QEQ test station and make changes based on that. Then run it back and forth until the vehicle passes.

Your also going to find that the tune that allows the truck to pass will not be the tune that allows the engine to run well. For example my unmodified 91 S10 4.3 would never pass emissions with the factory timing specs. Each time I would have to back the timing back to 4 degrees, disconnect and plug the vacuum advance, and pull the PVC hose plug it with an ear plug and then reconnect it. Once it passed I would undo that and drive it until the next time.

You may find that you need an "emissions" carburetor and a carburetor to drive it everyday along with different timing. This process should help make your yearly testing much less arduous.

Having your distributor spun on a distributor machine will also show any defects that may be in the distributor that are affecting the emissions. As an example we had a customer bring in a all original 70 Corvette that did not idle as smoothly as the owner felt it should. He had taken the car to several other places but the problem was never located. Once the distributor was spun it was very apparent the point lobes on the shaft were mis-machined from the factory. They were not equal distance apart from each other on the shaft. (About 4* different) This prevented about half of the cylinders from firing on time. Once a good used shaft was installed in his number correct distributor the car performed much better and idled as expected. This sort of thing would prevent a marginally clean engine from passing the test.

Can you post the results from the test that failed?

I will add that a A/F guage can help get your engine get better mileage but it only measures the fuel to air ratio whereas the emissions testing breaks down the air into its different components and that's what makes or breaks you.