Re: Recommend carb for 5.7 350
 

The truck runs fine to me and runs the same way since I bought it. The truck usually needs to be cranked a few times to get it going on a cold start. Need to give a bit of gas and rev for a bit to get it to idle without turning off. This is only on cold starts. When it is warmed up it turns on fine. Idle is a little rough but nothing that isn't understandable given the age of the truck.

As far as timing I have no clue on what it is set at, I'd need to get a timing light to find out or if there is another way to figure this out let me know.

There is a bit of a smell of gas in the exhaust so I believe that means it is running rich?

Re: Recommend carb for 5.7 350
 

I am with you and everyone else on the get a new mechanic part. I won't be going back there again. Now I'm on the camp to get this carb sorted out.

Re: Recommend carb for 5.7 350
 

With the lack of a working choke it will be a bit cantakerous starting.
You could get a timing light and check it.
Rich smell in the exhaust could just be lack of good hard use. You gotta blow the carbon out once in awhile.
If it runs good otherwise then why fuss with it.
If you want to learn how to check the timing just ask!

Re: Recommend carb for 5.7 350
 

Yeah it is running fine like it has been. If no one had mentioned about the 2 barrels not working I would have never known.

It would be nice to eventually fix it to get it starting smoother but not a major concern.

I suspected the choke was not working properly after talking with a friend who has a manual choke on his old chevy, but assumed it was automatic so never looked into it further.

I'll read up a bit more in the book and look at the choke and the linkages.

So, how would one learn how to check the timing?

Re: Recommend carb for 5.7 350
 

You need to know what is in the engine. A rough idle coulld mean a bigger than stock camshaft. Stock timing was around 8 to 10 degrees advanced before top dead center (BTDC).

Like I stated in your other thread... you NEED a timing light to get the timing nailed down before diagnosing any carb problems. Timing lights are a very important tool to have when working on old rigs. They aren't expensive either. Also... a good service manual (Chilton, Haynes) will give all the tune up specs.

Gary

Re: Recommend carb for 5.7 350
 

Simple.
Just google 'how to set timing on a sbc'.

Lots of sites come up. There's some threads on here and a write up in the FAQ section.
If it's set to stock timing it will be set at 4-6 degrees. With the crap gas we buy now you can bump it up to 12.
Don't get caught up in the discussions about recurving your distributor. Just look for how to check your basic timing.

Re: Recommend carb for 5.7 350
 

Alrighty, I'll go ahead and finally get a timing light than. I have the pdf copies of the service manual that have been posted on here as a reference but will get a Chilton/Haynes service manual as well.

Re: Recommend carb for 5.7 350
 

I hate Holleys! Yes they are easy to modify and parts are readily availible for them. There is a reason for that.
Q-jet's are the best for street use as stated earlier by other members. In the right hands a Q-jet is nearly unbeatable.

GET a new mechanic. You carb does look like a aftermarket rebuilder has had it recently. As such, the problem might lie with the Secondary air flap adjustment tension. On the right side of the carb where the airflap shaft come through the body... underneth this is a little allen head screw that adjusts the tension on a spring. MAKE small adjustments and road test. You should have a smooth and gradual, but very noticable increase in power and throaty noise. Not a big kick in the pants or slow transition.

Re: Recommend carb for 5.7 350
 

This!
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Re: Recommend carb for 5.7 350
 

There is one carb that beats a Q-jet. A well tuned Holley. :)

Holleys are less complicated than a Q-jet... but everybody makes them out to be a nightmare. Very easy to tune, and completely reliable. Most are dang near spot on out of the box. The old wives tales that you have to constantly tune a Holley are just not true.

Gary

Re: Recommend carb for 5.7 350
 

The old wives tale that you have to constantly tune any carb is the one that makes me laugh Gary!

Re: Recommend carb for 5.7 350
 

The 600CFM Holley is a great choice, but beware,; it could cost you a friend or two. Holley vs Quadrajet is one of those arguments like politics or religion. I prefer the Holley because I can set one up and when I'm finished it will stand up and dance the tango. I just never quite got the knack of setting up a quadrajet. For some reason I just can't get one quite right so I prefer the Holley. It all depends on you and your skills. If you have to pay someone to set it up, tear one or two apart and work with it until you can set it up blindfolded. Then go laugh at your tune-up guy. There is no such thing as a "bad" carb...only one that needs to be rebuilt.

Re: Recommend carb for 5.7 350
 

With your choke not working properly, the mechanism that allows the secondary's to open is also not working properly.

Fix that, or remove it, and you will enjoy the moan of that Q-jet like never before.

Re: Recommend carb for 5.7 350
 

I think Holley's popularity is due to them more simple and easy to tune. I don't think most people refer a Holley is a nightmare. They are reliable carb and people with limited tuning skills can put them on and roll.

With that being said, that doesn't make them "better". The smallest cfm Q jet is capable from flowing 750 cfm, IF the engine needs it, but most small blocks don't. Besides appearance, there's no advantage whatsover to any Holley vacuum secondary vs a Q-jet. Most people (including myself) think the Holley's look better or more impressive, especially a dual line Holley.

The bottom line is if you are using a vac secondary Holley on an engine, you are leaving economy and power on the table. The notion that a Q-Jet is only suited for a stock or low HP application is laughable. It takes a 750 double pumper to start getting close to a well tuned Q jet. Pontiac, Olds, and Buick guys have a tons of naturally aspirated 10 and 11 second cars with Q-jets.

I have a 800 cfm Q Jet (straight inlet Buick carb, actually) that I am going to run my on my '67 GTO that I used to use on a street/strip '69 Firebird years ago. I was running it on a Performer RPM intake on a healthy 440 cu in Pontiac (.060" over 428). My brother bought a new Quik Fuel 750 chokeless race carb when they came out, and we tried it on my Firebird. The 2 carbs ran .006 apart. It 60 ft'd better with the Q-Jet and ran a 1/2 MPH faster in 1/4 with QF. This was $600+ Race race carb vs a re-jetted stock Q-jet with choke flap still installed.

I'm not trying to be a Holley basher - I've ran tons of them, but its hard for me to put a Holley double pumper on a street driven engine with gas being $3.50 a gallon, and I am going to put a Holley vacuum secondary carb on an engine and give MPG AND power. When gas was cheap, I'd run the double pumpers on street cars, but I can't see doing that anymore unless its a just a toy ot street/strip car...

Re: Recommend carb for 5.7 350
 

If you look closely you'll see that his choke is completely off. Which means the secondary lock out is disengaged.
He's good to go.

Re: Recommend carb for 5.7 350
 

...

Re: Recommend carb for 5.7 350
 

I have never messed with an electric choke model, looks like it is still on the carb though...but with my old eyes I cant tell what's what in the pics.

Re: Recommend carb for 5.7 350
 

Cheese should not go on a turkey sandwich.

Re: Recommend carb for 5.7 350
 

I'm guessing it was on the discussion. On a discussion board. Where the OP asked for a recommendation for a carb for a 350. ;):uhmk::lol:


Just put a Predator on it and be done with!!! -lol

http://i41.tinypic.com/fmsylv.jpg

Re: Recommend carb for 5.7 350
 

Well this has turned into quite an active thread. I probably should edit my original post to say that now I am looking for help to fix the carb. Not looking to buy a new one or get a replacement.

Honestly this is the first carburetor engine I have worked on so all of this new to me. I want to learn so I can do all of this stuff myself. I'll keep on reading up on stuff to learn more.

Here are some more pics to see if you point out what is not hooked up properly.

Attachment 1145714

Attachment 1145715

Attachment 1145716

Re: Recommend carb for 5.7 350
 

Only thing I see wrong or out of place is the old choke stove and linkage rod still attached to your intake manifold. It might hang up your linkage so best to remove it. Should be a large phillips head screw that's easy to unscrew and remove it.
If you intend to make your choke work you'll need to run 12V to the black cap. To set the choke you loosen the 3 screws that hold the cap in place and rotate the cap. Hold the throttle open as you turn the cap and the choke plate will close.
Here's a link that explains your carb and choke.
http://www.vetteprojects.com/kstyer/quadrajet.htm

Re: Recommend carb for 5.7 350
 

Ok I thought it would need 12V. I assume it only needs 12V during ignition correct? I will run a 12V unfused ignition wire to the black cap. I should have one of those type of connections somewhere as I remember seeing lots of loose wiring underneath the hood not connected up at all. I think the PO forgot to hook it up.

Re: Recommend carb for 5.7 350
 

The shaft at the bottom rear of the carb that goes all the way to the other side is the secondary shaft, it has the pin that almost looks like a finish nail in it. Just in front of that there is a brass piece that is blocking that shaft from rotating, and is why your secondaries (second 2 of the 4 barrels) won't work.

Once you get the choke either working or removed, I bet the secondaries will work fine, looks like a recent rebuild.

This book was a big help to me with its diagrams of how things should be and explanations of how to get them that way.

http://www.walmart.com/ip/4890091?wm...599990&veh=sem

Re: Recommend carb for 5.7 350
 

good link. You guys have sold me on trying to get to know this quadrajet a little better before giving up and getting something else.

Re: Recommend carb for 5.7 350
 

Some more good links.
Read carefully John. There will be a test. LOL!
http://www.carburetor-blog.com/free-...epair-manuals/
http://www.buickpartsdirectory.com/carbs.htm
http://www.digitalcorvettes.com/foru...ad.php?t=88376