Some carb advice for a new guy.
 

I recently bought a 1968 GMC with the 283 Small block.
It has a 650 cfm Holley 4165 double pumper. The first issue is the manual choke on it was broken at some point and the PO wired it closed. Once I got it home I had to take care of some things on it before I could drive it so it ended up sitting for about 3 months.

I finally finished stuff up this weekend and got it running and driving again, but it was very hard to keep it running at first, it would only run for a couple of seconds at a time, then fire back up if you pumped the pedal then started it.

After a couple of different tries I noticed it was running longer each time and after about 5 attempts spaced 45 minutes or so apart it would run and idle fine.

After a short drive I turned it off and it would not start again, when I looked there was fuel puddled on top of the manifold. I tapped the bowls with a wrench, thinking a float might be stuck. Let it sit for an hour or so and then it fired right up and drove fine (no fuel on top of manifold).

So now my questions:
1.) I assume that the carb got a bit gunky or sticky from sitting for a couple of months. Does that seem reasonable given the description?

2.) does anyone know of a replacement manual choke kit for the 4165, or know if the one from Holley that lists the 4300, 4150, and 4160 will work with this carb? (the guy n Holley tech support did not seem to think it would work)

3.) a lot of my research indicates that the stock 283 would be happier with something in the 400-500 CFM range instead of the 650. I would like to hear thoughts on this as well.

I think it will cost around $140 for the choke replacement and a rebuild kit.
If a smaller carb would be better in general, then maybe replacement is a better route?

My plan for the truck is to try to get it to a good reliable driving state and have fun cruising it, not looking for fast, or lots of power. Low and slow is my style.

Re: Some carb advice for a new guy.
 

The problem keeping it running when cold is because you don't have a working choke system. It exists for a reason. If that 283 is stock, that is a fairly large carb for the engine but with a working choke should be able to be made to work. A vacuum secondary carb would be more forgiving in the driveability arena. Given how you want to drive and use it and if you want to keep this carb, make sure the secondaries aren't opening until fairly late in the primaries range of motion. Wouldn't hurt to have a good fuel filter involved in the fuel system. Do you know what jets and power valve are in the carb?

Re: Some carb advice for a new guy.
 

Pic of your carb and choke really would help.

Re: Some carb advice for a new guy.
 

This is the side of the carb where the choke would be attached. the cable is still there going in to the cab, but the carb side has just a tiny bit of wire left at the end of the cable and is not hooked up.

The second picture is a closeup and you can see where the choke is zip tied open.

Re: Some carb advice for a new guy.
 

You’re missing enough parts to warrant getting a new carb.

Re: Some carb advice for a new guy.
 

^ Yup!

Re: Some carb advice for a new guy.
 

Too much carb for that little 283.

Re: Some carb advice for a new guy.
 

Besides the choke, what else are you seeing missing?
A lot of people seem to like the Edelbrock 1404 for the smaller engines, that is the direction I am leaning.

Re: Some carb advice for a new guy.
 

A 500 cfm carb would be a good fit for a 283. A 650 is too much carb for that engine.

Re: Some carb advice for a new guy.
 

Secondary accelerator pump linkage is missin.
I’d steer clear of an edelbrock unless you really want to learn a bunch more about carb heat, fuel pressures, secondary bogging etc.
I’d go with a Holley 600. It’s a vac secondary so not to big.
Like this.


https://www.ebay.ca/itm/358098653001

Re: Some carb advice for a new guy.
 

FYI, the carb is a Q-jet replacement. There seem to be lots of different list numbers. What's really confusing in the exploded view below shows a secondary pump diaphragm, but also vacuum secondary housing, diaphragm, lever, etc. Below is some Holley documentation. Figure 1 shows you where the "list number" is stamped. That will give you further info on that specific carb.

https://documents.holley.com/199r8340-1rev.pdf

On another note: Yes, a stock 283 needs nowhere near 650cfm. However, I'm not sure your secondaries are even working! Holley does make a rebuild kit for your carb, but it doesn't include any external parts that may be missing. If that's a Q-jet manifold, you will need an adapter plate for a square bore carb. And I would be leery about buying a Chinesium Holley rip-off.

Re: Some carb advice for a new guy.
 

Just found this, which should help you to determine what is missing: It's several photos of a 4165 series, list 0-6210 carb. It's clearly a double pumper, not vac secondaries. The vacuum diaphragm you see is a choke pull-off.

https://www.oreillyauto.com/detail/c...tor/hly0/06210

Re: Some carb advice for a new guy.
 

Thank you all for the replies. Looks like a new carb is up next. Now I just need to get to the bottom of the Edelbrock vs Holley debate!

Re: Some carb advice for a new guy.
 

Yes, lots of people feel strongly each way! I used several of each over the years, from a 450cfm Holley Q-Jet replacement to a dual quad Edelbrock setup, which has worked exceedingly well for more than 5 years now. In fact, I did another one last year for a 302 Ford, and it's also been working great.

My favorites have been a Holley VS 650cfm 4150 series, and my truck's current carb--an Edelbrock 650cfm AVS2. Many times the smaller carbs, like a 390cfm Holley cost more than a 600cfm Holley like the 80457. Same is true of an Edelbrock 500 vs 600. If the truth be known, a stock 283 may not draw in enough air to open the secondaries of 600cfm carb, or maybe even a 500.

Edit: Have to add that that Edelbrock is often and bolt-on-and-go carb, where all you have to do is set idle speed and idle mixture. Holleys typically need a little more tuning, sometimes squirter, jetting, and power valve changes. There a lots of good resources for learning what components effect various carbs' operations. But the Edelbrock owners manual takes first place.https://67-72chevytrucks.com/vboard/...ons/icon14.gif https://www.edelbrock.com/media/wysi...ers-manual.pdf

Re: Some carb advice for a new guy.
 

Well, it was nice to meet you. Leave a trail of crumbs on your way down that rabbit hole.

Re: Some carb advice for a new guy.
 

<cough cough> quadrajet <cough> :devil:

Re: Some carb advice for a new guy.
 

Looks mint, full race to me

Re: Some carb advice for a new guy.
 

Well, since he's already got the manifold...

Re: Some carb advice for a new guy.
 

I have a souped up 292 L6 [Bored .030-over, Crane Cam, bigger valves, Offy intake, Clifford headers, etc.] and I run the Edel-1404 w/manual choke on my '68 C/10 Stepside.
Great carburetor.
I ran a Holley 4160, R8007, 390 CFM for 25 years, but it was always a pain -- blowing out power valves at every backfire, and needing constant tuning.
The Carter AFB design is much better for me.

Re: Some carb advice for a new guy.
 

Yah, I'm just being a troll

Re: Some carb advice for a new guy.
 

Advice: Carbs are not plug and play. You will need to dial them in. Combination of jets, needles, timing and I use a Air/Fuel sensor with gauge.
Or periodically, you get lucky and they work for your set-up right out of the box.

Re: Some carb advice for a new guy.
 

I don't have much to add. 650 double pumper is way too much for a 283 as said. I'm a Holley guy so I would lean that way BUT a properly built Quadrabog-I mean Quadrajet-is a very fine carb when done right. If you can find a reputable shop to build/sell you one that may be the way to go. Auto Zone used to sell Holley USA rebuilt Q-jets but the quality has gone downhill as I think they are not done in KY any more. I'm going to throw out a new one. Do you really need a 4bbl? What about a Holley 500 cfm 2 bbl? Would depend on how that intake is configured but might work.

Re: Some carb advice for a new guy.
 

Just to add what Mike B. said, I use the Edelbrock AVS2 with its annular flow primaries. They are relatively easy to tune. No cold start issues at all. I see there's a 500CFM version (Model 1901 or manual choke 1902), so that would probably do the trick. Reviews look good. But, as always, it's easy to spend other people's money! Looks like they're still made in the USA too.

https://www.summitracing.com/parts/edl-1901
https://www.summitracing.com/parts/edl-1902

Re: Some carb advice for a new guy.
 

The difference between the old Carter AVS and Edelbrock's new AVS2 is in the Metering Rods and Jets. Carter's AVS used three-stage Rods and Jets -- allowing mid-range tuning.
The Edelbrock AVS2 uses the same two-stage style Rods and Jets that are used on their Performer [AFB Clone.]
AFIK 3-stage Rods and Jets have entirely disappeared.

Re: Some carb advice for a new guy.
 

Not sure what you mean by 3-stage metering rods. I bought an AVS2 and a calibration kit (slight surging at part throttle). The rods in the kit are small at the tip, taper, and further up have a step. I suspect that that largest diameter doesn't actually enter the jet, given the carburetor configuration? I haven't changed anything yet, as it's a real mother female dog to get up there when I'm using a cane. At least I got the carb on and the truck running.

Re: Some carb advice for a new guy.
 

Brings back my own experience tuning my 1905 AVS2. A nice feature of the Edelbrock is the ability to swap metering rods and/or springs in a minute, adjust the idle mixture screws (if needed) and take another test drive. My neighbors were probably wondering what the hell I was doing driving in and out of the subdivision a bunch of times when I was tuning it. I printed out the calibration chart and kept track of the combinations tried and what I'm currently using. Also, it's a MUST to limit fuel pressure to Edelbrock carbs to no more than 4-6 PSI, so I added a fuel regulator and VDO #152002 gauge. That needs to be factored in on the carb decision as well.

I've uploaded a copy of the 500CFM 1901-1904 chart for any that may be interested.

Re: Some carb advice for a new guy.
 

Yes, the rod's main body doesn't go gown into the jet. So, there are only two stages, for example a .073" and .047". These rods would be stamped 073x047, but sometimes the numbers are almost impossible to read. So what you have to do is measure them with a micrometer or dial caliper.

At high engine vacuum (when cruising) we have the .073" diameter in, let's say, a .100" jet. But, when vacuum drops during acceleration, the rod lifts up and now its small .047" diameter is in the jet for a richer mixture. The rods work in conjunction with step-up springs to determine the vacuum at which they operate.

On at least some of the original equipment AFB carbs used on AMC, GM, and Chrysler performance engines, the rods had 3 stages, which would have made for ultra-fine tuning. I don't think the aftermarket universal versions of AFB carbs had 3 stages.

The metering rod equivalent on a Holley is the power valve, which is designed to open when manifold vacuum drops to a certain level adding more fuel for acceleration. The most common size being 6.5"hg for a mild performance engine.

Page 3 here is a better explanation of how the metering rods and springs work together. https://www.edelbrock.com/media/wysi...ers-manual.pdf

Re: Some carb advice for a new guy.
 

I know how a carb works. I also have the guide that came with the cal kit.

Re: Some carb advice for a new guy.
 

You asked a couple questions, but I guess I went overboard!

Re: Some carb advice for a new guy.
 

;) No biggee. Someone will get some use from it.

Re: Some carb advice for a new guy.
 

Way back when Carter still built carburetors they built the AFB -- Aluminum Four Barrel and the AVS -- Adjustable Vacuum Secondary.
When they quit the carb business [in the Mid '80s -- due to factory fuel injection] Federal Mogul took over building AFBs for the aftermarket. Edelbrock also got some AFBs from the same Weber factory still making them, and marketed them with a higher polish and emphasis on high performance parts.
To my knowledge, no one still built the AVS. [Until Edelbrock revived it fairly recently.] The original AVS carbs had three stage Metering Rods and Jets. The middle apertures were to dial in midrange performance. I have an old Carter AVS i found discarded as a prop after a movie wrapped. Instead of annular rings in the secondaries, it has 1/4'' x 2''[~] probes with many small holes. I bought Edelbrock AVS2 Rods and Jets in the hope of rebuilding it, but found they were only two-step. Edelbrock consolidated logistics by converting the AVS2 to use 2-step parts like their Performer [AFB]
Federal Mogul quit making AFBs in the early 2000s.
Guys at the local Hot Rod Shop said my rebuilt AVS would ''Probably run like ass anyway'' so I dropped the project.

:chevy:

Re: Some carb advice for a new guy.
 

That's some good AFB history there! Back in the late 60s, I bought an AFB that was OE on a 300hp/327 engine. The owner had decided to go with a Holley that was used on the solid lifter 327 (365hp?). I installed the AFB on a 292 (283 +.030") in a 57 Chevy. Don't remember which manifold I used.

That is still one of my all time favorite carbs. Every one of them was configured by the factory (GM, AMC, Chrysler) for a specific engine. I never even re-jetted mine, because it worked so well (and I wasn't very knowledgeable about carbs back then). Tried to find that exact model/part number many years later for a 327 that I had built. There were a few available on eBay and elsewhere, but prices were stratospheric.

Re: Some carb advice for a new guy.
 

I want to add that all Edelbrock Performer-series carbs use Air Valve Secondaries, not just the ones ones branded AVS and AVS2, which are adjustable. I copied this explanation from a Jeff Smith article:

"The AVS name is an acronym that stands for Air Valve Secondary. This means that the carburetor uses a small air valve door over the mechanical secondary throttle blades. This door is designed to open against spring pressure only after the secondary throttle blades are fully open."

What he didn't say is the air valve on the earlier Edelbrock carbs used a fixed weight instead of an adjustable spring. So instead of overcoming spring pressure, the air valve opened when air flow overcame the counterweight. Sometimes guys would lighten the weights, but that could introduce a bog.

Also, the AVS2 has a major improvement, and that's the annular boosters. Plenty of info about them in the Interment.